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PPMS ACT Manual - Materials Research Laboratory at UCSB

1. 1996 Physical Property Measurement System Horizontal Rotator Option User s Manual 1998 Physical Property Measurement System PPMS MultiVu Application User s Manual 1999 Service note 1070 802 PPMS software and firmware upgrade instructions Quantum Design PPMS AC Transport Option User s Manual Rev D 1 References 1 Index AC bias current range 1 1 AC board applying gain to signal 3 3 3 4 calibrated for specific hardware 2 2 3 5 installing 2 2 2 4 processing signals 3 5 ACT data files See Measurement data files Raw measurement data files ACT Helium 3 probe cable electrical interconnections 6 5 installing 6 2 ACT Horizontal Rotator probe cable electrical interconnections 7 5 installing 7 2 ACT measurements automating 5 3 data from saving See Measurement data files Raw measurement data files with Helium 3 system 6 2 6 4 with Horizontal Rotator 7 1 7 4 in immediate mode 5 3 5 11 operating modes comparing 5 4 sensitive avoiding noisy frequencies during 1 3 1 5 in sequence mode 5 12 5 19 types of 1 1 1 2 4 1 See also Critical current measurement Hall coefficient measurement I V curve measurement Resistivity measurement wiring sample for See Sample wiring ACT option See also ACT measurements ACT software automating operation of 1 1 4 1 See also ACT measurements Sequence mode calibration file 4 2 electrical connections for illustration of 2 6 A 1 hardware See AC boa
2. A major concern when measuring critical current in many superconducting samples is passing too much power through them once they become resistive Superconductors can support only a finite amount of supercurrent Once the current in a superconductor exceeds a certain value the material breaks down and becomes nonsuperconducting or resistive The current at which this occurs in a given superconductor is the critical current The ACT system provides power limiting through the sample during critical current measurements so that delicate samples such as thin films are not destroyed The current through the sample is stepped up by the digital signal processor DSP in small discrete steps towards a specified maximum current As the current increases the voltage drop across the sample is monitored As long as the sample remains superconducting the measured voltage should be zero When the sample becomes resistive the current through it generates a potential difference across the sample The ACT system averages this measured potential over a designated length of time in order to filter out noise Once the specified small critical voltage is found the current is shut off The ACT software reports the current at which the ramp is stopped The response time is approximately 40 microseconds when using the short averaging time and roughly 5 2 milliseconds when using the long averaging time To help reduce the effects of noise on the critical current measur
3. Figure 3 4 ACT Sample Puck Instead of using an ACT sample puck you may use a general purpose PPMS sample puck that does not have a circuit board with contact pads on its surface If you use a general purpose puck you ascertain the sample wiring from the information in table A 2 3 6 PPMS AC Transport Option User s Manual Rev D 1 Quantum Design October 15 2003 C HAPTER 4 Software 4 1 Introduction This chapter contains the following information e Section 4 2 presents an overview of e Section 4 4 discusses and explains how the ACT software and discusses the to create ACT data files AC Transport control center e Section 4 3 discusses the ACT status log 4 2 Overview of the ACT Software The ACT option software supports resistivity Hall coefficient and critical current sample property measurements as well as tracing I V curves Measurements may be taken immediately or taken within a PPMS MultiVu sequence file The ACT software is integrated into the PPMS MultiVu application so you may use PPMS MultiVu commands to automate ACT operation Measurements performed by the ACT system are defined by the measurement parameters such as the excitation frequency and acquisition time Measurement results and other relevant parameters reported by the Model 6000 PPMS Controller are stored in specified ACT measurement data files Table 4 1 Software Files Required to Operate ACT Option DIRECTORY FILES C QdPpms Actrans Non
4. Model 7100 AC Transport Controller Table 3 2 Voltage Detection Gain Stages PREAMP AC BOARD TOTAL GAIN MAX MIN VOLTAGE GAIN GAIN VOLTAGE FOR FOR STAGE STAGE xl xl xl 5V IV xl x5 x5 IV 200 mV x10 xl x10 500 mV 100 mV xl x25 x25 200 mV 40 mV x10 x5 x50 100 mV 20 mV x100 xl x100 50 mV 10 mV xl x125 x125 40 mV 8 mV x10 x25 x250 20 mV 4 mV x100 x5 x500 10 mV 2 mV x1000 xl x1000 5mV 1 mV x10 x125 x1250 4 mV 800 uV x100 x25 x2500 2mV 400 uV x1000 x5 x5000 1 mV 200 uV x100 x125 x12500 400 uV 80 uV x1000 x25 x25000 200 uV 40 uV x1000 x125 x125000 40 uV N A 3 2 4 Automatic Thermal Cutoff Chapter 3 Hardware The Model 7100 includes a thermal cutoff feature to protect the sample electronics and the current drive electronics The thermal cutoff feature automatically shuts off the excitation current when a set of resistors in series with the current leads becomes too warm When this happens the Voltage Limited LED on the Model 7100 front panel flashes until the resistors cool to an acceptable level The Thermal Cutoff Adjustment potentiometer on the rear panel of the Model 7100 may be used to change the thermal cutoff limit The setting of the Current Offset Adjustment potentiometer however should not be changed Figure A 2 illustrates the Model 7100 rear panel 3 4 PPMS AC Transport Option User s Manual Rev D 1 October 15 2003 Quantum Design Cha
5. Quantum Design PPMS AC Transport Option User s Manual Rev D 1 6 5 October 15 2003 C H APTER 7 7 1 7 2 Operation with the Horizontal Rotator Introduction This chapter contains the following information e Section 7 2 presents an overview of ACT e Section 7 4 describes how to take ACT operation with the Horizontal Rotator measurements when using the Horizontal Rotator e Section 7 3 explains how to configure the e Section 7 5 contains interconnection rotator thermometer tables for the ACT Horizontal Rotator probe cable Overview of ACT Operation with the Horizontal Rotator Many researchers find it useful to be able to rotate samples in the magnetic field of the PPMS sample chamber while measuring with the ACT system This can be accomplished by using the PPMS Horizontal Rotator option in conjunction with the ACT option However you must keep in mind some important considerations when you use the two options together to take measurements This chapter details those important considerations Using the ACT system with the Horizontal Rotator also requires the hardware supplied in the Horizontal Rotator kit for the ACT option part number 4084 308 The kit includes a special cable and special sample holder boards When the ACT system uses the Horizontal Rotator probe four of the sample chamber wires must be connected directly to the rotator thermometer Only eight wires rather than the normal twelve are available for ACT measu
6. p aeterne ter god i tee eer but erepti e ep rides 6 2 6 3 T I Prepare for the Measurement x seest eei tte eere e ad eT Et RE REPRE petes 6 2 6 3 1 2 Install the Sample ertt PER rr I PERF VERD PEE RM qe Ere ghe ERES need 6 3 6 3 1 3 Start Up the Software uu e e EE e dpt BU oin Ie AP deis ee edere oreet 6 3 6 3 2 Performing Measurements s erias rn eire Eee iren ea eee Ee ag ea edet ap ee Sh eee Seas SS chas eas tet 6 4 6 4 Interconnection Tables for the ACT Helium 3 Probe Cable sse 6 5 CHAPTER 7 Operation with the Horizontal Rotator sse tette 7 1 7 T Introduction ei ror E sh tag ai a io m M n c RE 7 1 7 2 Overview of ACT Operation with the Horizontal Rotator esee eren enne nennen 7 1 7 3 Rotator Thermometer Configuration eren nee ener enne nnen enne ne enee trennen enne tnen ne ennn nne 7 2 7 3 1 Turmng Off UserTerp 5 nen ren ie Bae tr a riy der eve Easa eR RENE REOR 7 3 7 4 ACT Measurements with the Horizontal Rotator essessesseeeeeeereeeeeneene enne nnne 7 4 7 5 Interconnection Tables for the ACT Horizontal Rotator Probe Cable sse 7 5 APPENDIX A Connections Ports and Pinouts 1727 0 siente ttetsn te ttnen tn ttntn teet es tate stes A 1 APM Introduction cotes aro tr eere devel ra m dst ee UD Ip RU teer OE A 1 1 2 ysteni Connections eor t oe endi te d E ede dui eti E E A 1 A3 Model 7100 Rear Panel
7. you upgrade the EPROMs Put the cover back on top of the Model 6000 and screw the cover into place Put the cover back on top of the electronics cabinet Turn on the Model 6000 PPMS AC Transport Option User s Manual Rev D 1 2 3 October 15 2003 Chapter 2 Installation Section 2 3 Installation Procedures Figure 2 2 Top View of Rear Portion of Model 6000 Interior Ouantum Design PPMS AC Transport Option User s Manual Rev D 1 2 4 October 15 2003 Chapter 2 Section 2 3 Installation Installation Procedures 2 3 2 Install the Model 7100 1 UseaPhillips head screwdriver to remove the four screws that hold the blank panel located below the magnet controller and magnet power supply on the front of the PPMS electronics cabinet Then remove the blank panel from the cabinet Refer to figure 2 3 Ee If you have an older PPMS electronics cabinet which does not use the I d refrigerator style door shown in figure 2 3 you must also remove the NOTE large blank panel from the front of the electronics cabinet Remove the four screws that hold the large blank panel in place g c Figure 2 3 Removing the Blank Panel 2 Use the four blank panel screws to position the Model 7100 below the Model 6000 In older cabinets the Model 7100 goes immediately beneath the magnet controller and magnet power supply Have someone help you by holding the Model 7100 while you tighten th
8. 3 6 3 NULL THE OFFSET VOLTAGE Prior to performing any five wire Hall coefficient measurement you null the offset between the nega tive and positive voltage leads You use the Balance potentiometers on the front panel of the Model 7100 AC Transport Controller to select a voltage that is between the two positive voltage leads Complete the following steps 1 2 3 4 Quantum Design Set the magnetic field to zero and wait for the system to stabilize at zero field Select Measure Balance Meter The Balance Meter dialog box opens see figure 5 3 Select the sample you will measure Select the resolution if necessary In most cases the Auto resolution is sufficient PPMS AC Transport Option User s Manual Rev D 1 5 15 October 15 2003 Section 5 3 ACT Measurements 5 T 8 1 2 5 3 7 sm NOTE 2 5 16 Chapter 5 Measurements Select a drive current You should specify the largest possible drive current that will not rail the electronics or destroy the sample A large drive current produces a large signal so it is easier to zero the signal Instead of selecting a very large drive current you can alternatively select the drive current that is closest to the measurement current Select Start Turn the Balance potentiometer for the appropriate channel until the offset is as close to zero as possible The Balance pots are on the front panel of the Model 7100 Watch the display area at the bottom of the
9. ACT Measurement Types The ACT option supports four types of electrical transport current measurements e Resistivity e Hall Coefficient e I V Curve e Critical Current Resistivity I V curve and critical current measurements measure the resistive voltage of the sample I V curve and critical current measurements are basically variants of a resistivity measurement All three of these measurement types require the same lead connections to the sample Hall coefficient measurements however measure the sample s Hall voltage and therefore require a different config uration for the sample lead connections 1 3 1 Resistivity Measurements The ACT option supports four terminal alternating current resistivity Sample measurements In ACT four terminal measurements two leads pass a current through the sample two separate leads are used to measure the potential drop across the sample and Ohm s law is used to calculate the sample resistivity figure 1 1 The voltage leads draw very little and ideally no current so the current through the sample and the potential drop across the sample can be known to a high degree of accuracy I V V l virtually eliminating the effects of lead and contact resistance Figure 1 1 Leads for hel Four Wire AC Resistivity The resistivity p is calculated by Measurement p VA I Equation 1 1 where V is the measured potential drop across the sample and is the current through the sample You
10. BUTTONS The Hall Coefficient Resistivity IV Curve and Critical Current command buttons in the AC Transport control center define and run Hall coefficient resistivity I V curve and critical current immediate mode measurements respectively Tutorials in chapter 5 explain how you use the control center command buttons to run ACT measurements in immediate mode PPMS AC Transport Option User s Manual Rev D 1 Quantum Design October 15 2003 Chapter 4 Section 4 3 Software ACT Status Log 43 ACT Status Log The ACT status log records high level hardware and software activity during ACT measurements and during system hardware checks it records the test results The ACT status log also captures warnings errors and informational messages that were generated since the ACT option was last activated The status log displays the results of only the active ACT session although it keeps a record of all ACT sessions The ACT status log captures more types of information than the PPMS MultiVu event log The View ACT Status Log command activates the status log The name of the default status log file is act 00001 10g You use the ACT status log to review a finished measurement or hardware check and to search for any problems that might have occurred Because the status log records important measurement informa tion you may be absent when a sequence file runs you simply review the status log after the sequence run is finished im ACT Logfile a
11. Balance Meter dialog box Notice that there is a delay between when you adjust the pot and when the offset is indicated in the Balance Meter dialog box so turn the pot slowly when the offset approaches zero Lock the Balance potentiometer in place once you have balanced the positive voltage leads as precisely as possible Simply press the tab on top of the knob clockwise 5 3 6 4 RUN THE SEQUENCE Select the Run Sequence button in the PPMS MultiVu tool bar You have saved your new sequence so it should run immediately Wait for the sequence run to finish While the sequence runs status messages in the sequence control center and the sequence status panels indicate that a sequence is running The commands in the sequence determine the length of time the sequence runs When the run is complete all Run commands are enabled and the sequence control center and the sequence status panels both indicate the sequence status is Idle The sequence measurement data is automatically saved to the data file you selected in section 5 3 6 2 Taking I V Curve Measurements in Sequence Mode For detailed information about creating and editing sequence files and for a discussion about all standard PPMS sequence commands refer to the Physical Property Measurement System PPMS MultiVu Application User s Manual 5 3 7 1 CREATE THE SEQUENCE COMMAND Select a new or existing sequence file Select the IV Curve measurement command which is in the Me
12. Manual Rev D 1 Quantum Design October 15 2003 C H APTER 3 Hardware 3 1 Introduction This chapter contains the following information Section 3 2 discusses the operation of the Model 7100 AC Transport Controller Section 3 3 discusses the ACT option AC board Section 3 4 discusses the ACT cables and jumpers Section 3 5 discusses the ACT sample pucks 3 2 Model 7100 AC Transport Controller The Model 7100 AC Transport Controller controls the operation of the ACT system The Model 7100 includes the following components Driver board with current and voltage amplifiers Low noise preamp board Ports for connection to AC board installed in Model 6000 PPMS Controller Ports for connection to sample BNC connectors to monitor current and voltage across sample LEDs indicating controller status Potentiometers for offset nulling between parallel positive voltage leads Quantum Design October 15 2003 amp AG TRANSPORT CONTROLLER ie ad 3 uc Figure 3 1 Front Panel on Model 7100 AC Transport Controller PPMS AC Transport Option User s Manual Rev D 1 3 1 Section 3 2 Chapter 3 Model 7100 AC Transport Controller Hardware Caution 3 2 1 3 2 To excite the sample the driver board receives and amplifies the signal from the AC board s digital signal processor DSP The preamp board detects the sample
13. Mount the sample on a Helium 3 sample mount part number 4092 610 Note that at temperatures below 1 K intimate thermal contact between the sample and the copper holder is very important to reduce temperature errors A thin film of Apiezon N Grease works well to aid thermal contact Apiezon N Grease is supplied with the Model P825 Helium 3 insert 2 Refer to figure 6 2 below to wire the sample to the stage The plug in sample mount is labeled for use with the user bridge board but by following the wiring schematics in figure 6 2 you can use it with the ACT option The labels on the sample mount are not correct when you use the ACT Helium 3 probe cable shown in figure 6 1 CHI CHI CH1 A ve i 3 4 n vee 3 V E Fe V V a ee ee 8 10 9 7 s CH2 CH2 CH2 A 5 WIRE HALL ON CH1 B 5 WIRE HALL CH1 C 5 WIRE HALL CH1 AND AND RESISTIVITY CH2 RESISTIVITY CH2 ALTERNATE 6 s TUE 3 Vz V l 3 4 I V V I 3 JE OO S isi V V4 I V V ds Be hoe oer OF Beto e net gt RESISTIVITY ON C E RESISTIVITY ON CH 2 Figure 6 2 Sample Wiring Diagrams for the Helium 3 Option 3 Attach the plug in sample stage to the Helium 3 refrigerator probe Refer to the Physical Property Measurement System Helium 3 Refrigerator System User s Manual for detailed ins
14. Ports 5 e tete re EE a S da bee E EEE e E eaS A 2 hwsaum iig PEE A 3 AA E Sample Connections 2 1 sehen epee i ein eee nen ei A 3 A 4 2 Drive Access and Monitor Conmections ccsccsscesseesseeseeeseeesceeceseceseceaecsaeceaecaeecaeeeaeeeaeseneeeeeeereeeeesees A 5 A 4 3 AC Board Connections d ici c etie ere re et Pe es e toc PUE RE eee bea d re saree eis gs eis e A 6 APPENDIX B Error and Warning Messages sse eterni tette ttti tete tette teretes B 1 B lIntroduction iscritte RU E P HE REUNIR trie MEE agis B 1 B 2 Warning Messages sia eth a eed BI RH RI ERN RENE ORI Cete a s ine ATA REDE B 1 B 3 Error Messages 5a te I hi eit epe ep ir e D ese A ER IG EA Ir evens do B 2 APPENDIX C Measuring the Hall Coefficient of the Copper Hall Sample sss C 1 Ou M introduction eEREEE O E C 1 C 2 Verifying the Hall Effect Measurement seesseeeeeeeeee eene enne ener trennen et nene nne ennn ne enne trennen enne C 1 BE CTT INES oo Si dats focaccia tdt hub tug sieeve omi dpt sto mood RE References I Index esee Sans Aceh tea een Ue RA Te AA ira eee Index 1 Quantum Design PPMS AC Transport Option User s Manual Rev D 1 iii October 15 2003 Contents Table of Figures Figures Figure 1 1 Leads for Four Wire AC Resistivity Measurement eeeseeeeseeeeeeeeeneeenen eene 1 2 Figure 1 2 Common Lead Arrangement for Bar Shaped Samples s
15. Status bar indicates the progress of an on going measurement and summarizes the results of the last measurement Color coded warning and error messages in the Status bar alert you to possible problems Warning messages appear on a yellow background Error messages appear on a red background Appendix B lists the warning and error messages 4 2 1 1 INSTALL TAB Instructions in the Install tab guide you through the procedures you complete to insert a sample into or remove a sample from the PPMS sample chamber The Sample Status panel in the Install tab always identifies the current status of the sample chamber AC Transport Control Center lel Es Install Data File Sample 1 Sample 2 waveform Configure Sample Status Purged and sealed Press VENT to vent the chamber and allow insertion or removal of the sample Vent Help Hall Coefficient He E IV Curve Critical Current Status Measure complete Good Gain at 5000mY Range Figure 4 1 Install Tab in AC Transport Control Center PPMS AC Transport Option User s Manual Rev D 1 Quantum Design October 15 2003 Chapter 4 Section 4 2 Software Overview of the ACT Software 4 2 1 2 DATA FILE TAB The Data File tab indicates which measurement data file and raw measurement data file will save sample measurement data and raw voltage data respectively If no measurement data file has been selected the File Name and Capture Raw Data panels are blank Sample measu
16. V plots can help illustrate the behavior of a sample or device and may be especially interesting when nonlinear behavior exists Figure 1 6 shows a plot of I V data for a diode at three different tempera tures The data was obtained by starting at zero current and ramping up to 100 uA Origin was used to plot the data l V Trace for a Diode at 3 Different Temperatures Using the Quantum Design AC Transport 150K 100K 50K 0 0 J i n i L i F i F i J 0 0 0 2 0 4 0 6 0 8 1 0 1 2 Voltage V Figure 1 6 Example I V Curve When the ACT software is started it automatically measures the power line frequency Each I V data point is obtained over an integral number of line cycles to help reject power line noise The zero excitation baseline voltage may also be measured prior to each I V curve measurement and subtracted from the entire set of I V data by using the Remove Voltage Offsets setting 1 6 PPMS AC Transport Option User s Manual Rev D 1 Quantum Design October 15 2003 Chapter 1 Section 1 3 Theory of Operation ACT Measurement Types 1 3 4 Critical Current Measurements As an ohm meter already set up to measure samples within the thermally controlled environment of the PPMS the ACT option provides a convenient method of determining the critical current of samples Physical connections to the sample for critical current measurements are made just as they are made for resistivity measurements see section 1 3 1
17. display area indicates the ideal measurement results The actual measured waveform is shown in black The light blue curve is not visible if the measured waveform and ideal plot are nearly identical Compare drawings A C and D in figure 4 4 below The plot in the Waveform tab is overwritten each time you run another measurement AC Transport Control Center C Tx AC Transport Control Center oP x Install Data File Sample 1 Sample 2 Waveform Configure Install Data File Sample 1 Sample 2 Waveform Configure Amplitude 0 mV Hall Coefficient f viu IV Curve Critical Current Status Measure complete Good Gain at 5000m Range isth IV Curve Critical Current Status Measure complete Good Gain at 5000m Range A Sine wave indicating good signal reading B Flat line indicating no signal was read Install Data File Sample 1 Sample 2 Waveform Configure Install Data File Sample 1 Sample 2 Waveform Configure Hall Coefficient t tivity i IV Curve Critical Current Hall Coefficient De ii IV Curve Critical Current Status Measure complete Good Gain at 5000m Range Status Measure complete Good Gain at 5000m Range C Very noisy signal was read D Distorted signal was read Figure 4 4 Waveform Tab in AC Transport Control Center Quantum Design PPMS AC Transport Option User s Manual Rev D 1 4 5 October 15 2003 Section 4 2 Chapter 4 Overvie
18. for four wire resistivity measure ments Sections 1 3 2 and 1 3 2 1 discuss technigues for connecting leads for four wire and five wire Hall coefficient measurements Chapter 6 includes important information about using the ACT system with the Helium 3 Refrigerator System option Chapter 7 includes important information about using the ACT system with the Horizontal Rotator option Appendix A includes a table of solder pad descriptions for the PPMS sample pucks When you use PPMS sample pucks make certain that for five wire measurements you tie together the V leads for the appropriate channel You should also refer to the appropriate option manual for information about securing the sample to the sample holder and for further sample mounting information Due to the high sensitivity of the ACT option it is important to use the option to perform only true four wire and five wire measurements Keep this in mind when you are attaching leads to the sample Even with true four wire and five wire measurements accuracy can be compromised if contact resistance is too high or grossly mismatched Once the sample is properly mounted on the sample holder remember to write down the sample s voltage lead separation and current cross sectional area This information is saved in the header of any new data file you create to store the sample measurement data 5 2 PPMS AC Transport Option User s Manual Rev D 1 Quantum Design October 15 2003 Chapter 5
19. into the PC and select the A drive Select the PPMS 32 bit Tools icon on the PC desktop and then run the Romcfg32 utility Select Send to PPMS Send Config in the main menu Select the A drive which is the drive where the rotator configuration files are located Qv e aS Select the HRACT cfg file where represents the serial number for your rotator The HRACT cfg file directs the thermometer calibration data to the system bridge board The HRf cfg file directs the thermometer calibration data to the user bridge board for use with the Resistivity option and the standard user bridge cable supplied with that option The Physical Property Measurement System Horizontal Rotator Option User s Manual explains how you configure the user bridge board to read the rotator thermometer Both HRACT cfg and HR cfg also configure the motor for proper step sizes according to which type of motor you are using Configuration files for high resolution motors have H at the end of the file name 7 Select OK Install the ACT Horizontal Rotator probe cable by plugging the connectors on the cable into the ports indicated by the cable labels Refer to figure 7 1 e Plug the 14 pin gray Lemo connector into the gray color coded port on the probe head e Plug the connector on the cable labeled P1 Sample Current Out into the P1 Sample Current Out port on the rear of the Model 7100 e Plug the c
20. is constructed is thin and fragile and can easily bend or dent Remove the Helium 3 refrigerator probe from the sample chamber Refer to the Physical Property Measurement System Helium 3 Refrigerator System User s Manual for detailed instructions Quit the Helium 3 software application if the application is running Install the ACT Helium 3 probe cable part number 3084 518 by plugging the connectors on the cable into the ports indicated by the cable labels e Plug the 14 pin gray Lemo connector into the gray color coded port on the probe head e Plug the connector on the cable labeled P1 Sample Current Out into the P1 Sample Current Out port on the rear of the Model 7100 e Plug the connector on the cable labeled P5 Sample Voltage In into the P5 Sample Voltage In port on the rear of the Model 7100 e Plug the 4 pin Lemo connector on the cable labeled P1 User Bridge into the P1 User Bridge port on the rear of the Model 6000 PUER P CURRENT OUT AC TRANSPORT WITH HELIUM S I P5 SAMPLE s ES Ses Figure 6 1 ACT Helium 3 Probe Cable PPMS AC Transport Option User s Manual Rev D 1 Quantum Design October 15 2003 Chapter 6 Operation with the Helium 3 System 6 3 1 2 1 Section 6 3 ACT Measurements with the Helium 3 System INSTALL THE SAMPLE
21. measure A sequence mode measurement command can instruct the system to measure both samples The system measures sample 1 then it measures sample 2 The immediate mode measurement dialog boxes show the results from the last measurement of that same type see figure 5 2 for example The sequence mode measurement dialog boxes do not show measurement results but you can use them to select which system data items you want to save to the specified ACT measurement data file see figure 5 8 Ex You are encouraged to use the AC Transport control center to perform oO all normal system operations The automated routines in the control NOTE center help ensure that you complete the necessary procedures when you install new samples and create data files The examples of immediate mode measurements in this chapter illustrate use of the control center 5 3 1 Taking Resistivity Measurements in Immediate Mode 5 3 1 1 PREPARE FOR THE MEASUREMENT 1 Mount the sample on a sample puck and connect the sample leads so that you can perform a four wire resistivity measurement Refer to section 5 2 A thin copper sample is also provided for demonstrating the Hall effect See Appendix C for more details 2 Insert the sample into the sample chamber Select the Install tab in the AC Transport control center and then follow the software prompts Quantum Design PPMS AC Transport Option User s Manual Rev D 1 5 3 October 15 2003 Section 5 3 ACT Mea
22. the offset is indicated in the Balance Meter dialog box so turn the pot slowly when the offset approaches zero Lock the Balance potentiometer in place once you have balanced the positive voltage leads as precisely as possible Simply press the tab on top of the knob clockwise 5 3 2 3 DEFINE THE MEASUREMENT 1 5 6 Set the appropriate magnetic field for the measurement You can continue defining the mea surement but should not run the measurement until the field has stabilized Select the Hall Coefficient button in the AC Transport control center The Hall Coefficient dialog box for an immediate mode measurement opens Items in the upper part of the dialog box designate measurement conditions that should be set prior to selecting the Measure button Items in the lower part of the dialog display the results of the last Hall coefficient measurement PPMS AC Transport Option User s Manual Rev D 1 Quantum Design October 15 2003 Chapter 5 Measurements Caution Ouantum Design Section 5 3 ACT Measurements ACT Hall Coefficient lel x r Excitation Last Measure Amplitude 10 m Tene p K Frequency 2 Hz Field 70000 Oe Duration h Sec Position E deg Settings Always Autorange IV Constant Current Mode Sticky Autorange Small Coefficients Mode Fixed Range v Z m Hall Coefficient Sample 1 C Sample 2 we mum T a fener 313 dB Ad ori
23. when you are deciding which measure ment parameters to use or if you are concerned about signal quality A clean single wavelength sine wave is optimal in the case of AC resistivity and Hall coefficient measurements However saving raw data creates very large data files You should disable the Capture Raw Data check box when raw voltage data is not required Section 4 4 1 explains in detail how you create an ACT measurement data file Quantum Design PPMS AC Transport Option User s Manual Rev D 1 4 3 October 15 2003 Section 4 2 Chapter 4 Overview of the ACT Software Software 4 4 4 2 1 3 SAMPLE TABS You use the Sample 1 and Sample 2 tabs to define sample properties when you are creating a measurement data file After you prompt the ACT software to create a file the Sample 1 tab automatically opens You use the Next and Back buttons to move back and forth between the two Sample tabs Entering sample property information in the Sample 2 tab is necessary only when a sample is wired to channel 2 on the Model 7100 AC Transport Controller AC Transport Control Center CE X AC Transport Control Center f x Install Data File Sample 1 Sample 2 Waveform Configure Install Data File Sample 1 Sample 2 Waveform Configure Material feu Material cu Comment Comment Voltage Lead Voltage Lead Separation ro cm Separation ro em o Back Cross d fo n2 iE Cosce pooo one Finish Datafile Title Lancet Datafile T
24. with Negative Charge Carriers The most accurate method of obtaining Hall coefficients is to examine how the Hall resistivity Res Ch1 for channel 1 varies with the magnetic field The ACT option does not care how you connect leads to the sample that is the instrument cannot distinguish between the transverse Hall voltage and the longitudinal voltage that is due to sample resistance Therefore a plot of p versus field for a sample wired for a Hall measurement should yield a straight line with slope R in units of Q cm Oe 10 cm coulomb You can easily use the ACT option to perform this operation but it is time consuming because you must change the field Notice that equations 1 1 and 1 3 differ only slightly From a computational standpoint R p B For observing trends in the dependence of R on other parameters such as temperature it may prove more efficient to use the single point Hall coefficient measurement built into the ACT option Note that the column in the data file reporting raw voltage is the peak to peak voltage amplitude which is always positive However the resistivity is calculated using the in phase component of the AC voltage A thin copper sample is provided with the AC Transport option and can be used to demonstrate the Hall effect It is stamped in the five wire configuration see section 1 3 2 1 and can be easily mounted to the AC Transport Puck See Appendix C for more information on the copper Hall sample 1 3
25. 2 1 ADDITIONAL VOLTAGE LEADS AND BALANCING The configuration for a four wire Hall coefficient measurement shown in figure 1 3 confirms the premise of the Hall effect However the Hall field is superimposed on top of the bias field from the two current leads so accurately measuring the Hall potential with a four wire measurement can be difficult To measure only the potential difference due to the Hall potential the voltage leads must delineate a perfect perpendicular to the bias field If this is not the case the measured potential V can have some component that is dependent on the magnitude of the electric bias field and on the sample resistance V which in turn may be temperature or magnetic field dependent as illustrated in figure 1 4 This resistive component is typically much larger than the Hall potential Vj Both the Hall potential and this offset depend on the bias current so this effect cannot be removed with AC filtering techniques You can account for this effect by attaching a fifth voltage lead in parallel to one of the other voltage leads figure 1 4 While the magnetic field is turned off a potentiometer between the two leads is used to null the offset that is due to the sample resistance Then once a field is applied the measured potential drop gives only the Hall potential plus components due to instrumental nonidealities that can be removed with AC filtering techniques Note that due to the small magnitude of the Ha
26. 2 3 1 Install the AC Board anna tc he ARS Haak halen ah S n ORAL AI 2 2 2 3 2 Install the Model 7100 cree etr cem eere entre e nee ed de tre eee ci 2 5 2 3 3 Connect the System tdt OUT ERREUR ERU SERE UE ER REDE i EES e EHE Ser et eo eg 2 6 2 324 Install amp he SOftWares c estostetetenisser e eed REED 2 6 CHAPTER 3 HardWate 4 nennen atte mon ate eidem Ae Ve frd ire sei idt tr Ve es 3 1 Be T Intr ducti n 5 5 e RR t du temen EO e e 3 1 3 2 Model 7100 AC Transport Controller 5 ioi doter ette tete eere ipee nl eere 3 1 3 2 1 Electrical Current Operating Modes sessi eene enne enne Ear nnnn nennen nnne 3 2 3 2 2 Qutput Range eoe eon e eerta tiec nono rd re tr e a ioo i eerie 3 3 3 2 3 Gain SettIngs tan atate ro EEG EE REO ERU DDR UE e E ER OPE ao puto 3 3 3 2 4 Automatic Thermal Cutoff c cccccccsscssecssscecsecsesceessecssccecsaecseeeecsaecseeeeesecsseeessaeceeesesseseeeeesaecseseesaeens 3 4 3 3 Mod l 6000 AC Board eicere err He ere en se dite Cote RUE att one cows da RR Tree Ree UE e eee ee EGRE dun 3 5 3 4 Cables and Jumpers vise a ee oe ete o e e e e e ir Re tree p eec 3 5 So ACT Sample PUCks subest eene pee dda eed Neha eis ides hel eH 3 6 Quantum Design PPMS AC Transport Option User s Manual Rev D 1 i October 15 2003 Contents Table of Contents CHAPTER 4 SoftWare M eines EAH ARR R 4 1 C SMS UTE re 4 1 4 2 Overview of the ACT SOftWaTe 5 eua RUD ARR AID RR IRA AIR E Deed n
27. Conventionsin the Manual size er rer ER E ERR mmmmmmmrirmmmmrmmmmrmmmmmmmmmmmmiHcauacmrra viii CHAPTER 1 Theory of Operation n o IRR RERESN UE ici ERR UR SER REUS UN ovine atone aOR 1 1 I IntroductiOnz uie eR E ERR HER RH teer s evi re Mte e Eee 1 1 L2 Qverview of the ACT ODtoOT 5i me Dee Cha sa gs dh ce EE IU De Beet p IRR E ER eva dha ae 1 1 1 3 ACT Measurement Ty pes 22 aee ate eit EA Ie eee ie ree e eter 1 2 1 3 1 Resistivity Measurements bte dede et ttes t der iate teet alae ai be d dee Ho aptae cete tete 1 2 1 3 1 T Harmonic Detection ere eee ree ret eH p Rad RI HE 1 3 1 3 2 Hall Coefficient Measurementt ccccccscccesscesscecesscesscecssecesscecssesesseecsaesessecsseeeesseceseeeessecesseseeseecsaeeeeaaes 1 3 1 3 2 1 Additional Voltage Leads and Balancing eese enne nne 1 4 1 3 2 2 Harmonic Detect100 SUB DR E E E EMUIMBeME 1 5 1 3 3 EV Curve Measurements tee cepere coe tede ipee ve runde Edo eere dae a de snas ve un Eee Reg eaae seas 1 6 1 3 4 Critical Current Measurements esses eene eene enne nennen tentent senes irren entrer tns en seen sereni 1 7 CHAPTER 2 TSCA GOR es estilo sea hho nce ee eta do EI ad enc READ e aut a 2 1 SAN IM 066 L116 ATI AAE RA oerte AT E ee ease 2 1 2 2 Installation Kit Components 2 recie Eee esie A quhip aireamh Genesis e ettet xe RR 2 1 2 3 Installation Procedures ete een EG RI EH EE ORE ERE EUR VERRE ER RR RC HET 2 2
28. October 15 2003 A P PEN DIX A Connections Ports and Pinouts A l Introduction This appendix contains the following information e Section A 2 illustrates the ACT system e Section A 4 contains the ACT system connections pinout tables e Section A 3 describes the function of the electrical ports on the Model 7100 A2 System Connections Figure A 1 illustrates the electrical connections for the ACT hardware o bi m D O O Oo ZA 3084 512 i kd iod CNN j P4 DIGITAL P3 ANALOG P2 DRIVE ACCESS P1 SAMPLE INTERFACE INTERFACE AND MONITOR CURRENT OUT bo T 8 PROBE HEAD MODEL 6000 00 p MODEL 7 3084 516 Figure A 1 ACT Connections Notice that to use the ACT option the PPMS must also be connected as for normal system operation except that the connection to the Model 6000 PPMS Controller P1 User Bridge port is not required The Physical Property Measurement System Hardware Manual identifies all PPMS electrical connections Quantum Design PPMS AC Transport Option User s Manual Rev D 1 A 1 October 15 2003 Section A 3 Appendix A Model 7100 Rear Panel Ports Connections Ports and Pinouts A 3 Model 7100 Rear Panel Ports Table A 1 describes the fun
29. Ouantum Design EA Mm all Physical Property Measurement System AC Transport Option User s Manual Part Number 1584 100 D 1 Ouantum Design 11578 Sorrento Valley Rd San Diego CA 92121 1311 USA Technical support 858 481 4400 800 289 6996 Fax 858 481 7410 Fifth edition of manual completed October 2003 Trademarks All product and company names appearing in this manual are trademarks or registered trademarks of their respective holders U S Patents 4 791 788 Method for Obtaining Improved Temperature Regulation When Using Liquid Helium Cooling 4 848 093 Apparatus and Method for Regulating Temperature in a Cryogenic Test Chamber 5 311 125 Magnetic Property Characterization System Employing a Single Sensing Coil Arrangement to Measure AC Susceptibility and DC Moment of a Sample patent licensed from Lakeshore 5 647 228 Apparatus and Method for Regulating Temperature in Cryogenic Test Chamber 5 798 641 Torque Magnetometer Utilizing Integrated Piezoresistive Levers Foreign Patents U K 9713380 5 Apparatus and Method for Regulating Temperature in Cryogenic Test Chamber C ONTENTS Table of Contents PREFACE Contents and Conventions sss tette tette treten treten nne vii Pl Introduction 25D UII O AE AE IU vii P2 Scope of the Manual eire tercie te e e OE te Pete RP ee Va oie da e veter iet dd vii P 3 Contents ot the Manual uepioWosnRRODSGOR ROB oes OR URBI OBRA GRIS vii P 4
30. Prepare for th Measurement notera n ec d eO D te den PEDE ita 5 5 3 3 2 2 Null the Offset Volt ge 3t mat ein att eo reb p t ree n DERE 5 6 3 3 2 3 Define the Measurement gne iei e Enero teu c eec bino tete eii 5 6 3 3 2 4 Run the Measurement een d n EO AIR E a ues D IR E I dp Ee d ipae ted 5 8 5 3 3 Taking I V Curve Measurements in Immediate Mode esee 5 8 5 3 3 1 Prepare for the Measurement eese eene nn innere nennen ne E EEEE enne 5 8 5 3 3 2 Define the Meas r MEI eoe teta tee pr nee RE OT epa 5 8 5 3 33 R n the Measurement nteger er e re eo e ei ie epe 5 10 5 3 4 Taking Critical Current Measurements in Immediate Mode eese 5 10 5 3 4 1 Prepare for the Measurement sinio ie orinn i eene ener trennen inneren nennen E E EE R o Eis 5 10 5 3 4 2 Define tbe Measurements srr reti eoe R EET e ER E R E RC Sa isea RSE 5 11 5 3 4 3 Run the Measurement sniene re cn o eret E Re CO SE tete erbe EE E E Set ao rete eed 5 11 5 3 5 Taking Resistivity Measurements in Sequence Mode eeseeeseeeee eene eere 5 12 9 3 5 1 Create the sequence Conimand 2 ete cre etiem eerte eere tide oo ge reve og 5 12 3 3 5 2 Prepare fot the Measurement eire ate eoo ntn eue iet spite te rh ex asa s s 5 13 5 3 5 3 Runithe Sequence ite Ebo bea toe depre obiter 5 14 5 3 6 Taking Five Wire Hall Measurements in Sequence Mode eee 5 14 5 3 6 1 Create the Seq
31. Sample 2 Dev Measure Save Close p Figure 5 6 Dialog Box for Defining Critical Current Measurement in Immediate Mode Use the Max Current text box to specify the maximum current in milliamperes used across the sample The Model 7100 provides as much as 2 A of current This large current can damage samples and other equipment in the current path Use only currents that can be safely handled by all hardware and samples in the circuit Use the Critical Voltage text box to specify the critical voltage in millivolts that causes the measurement to stop and report the drive current as the critical current Use the Power Limit text box to specify an approximate power limit in milliwatts The power limit is intended to protect the sample and is not a tool for precision measurement purposes and it is calibrated with this in mind Specify the re cool time in seconds the software waits between repetitions of the measurement Select the averaging time The averaging time can be Long Medium Short or Line Longer averaging times make the measurement less susceptible to noise but lengthen the response time once the critical voltage is reached The longest averaging time is the Line selection which greatly reduces the effects of noise by monitoring the voltage for an entire power line cycle Specify the number of measurements The result will be the average of these measurements Select the sample Sample 1 or Sample 2 y
32. Section 5 3 Measurements ACT Measurements 5 3 ACT Measurements ACT measurements can be taken only if the ACT connector cables are KE plugged into the correct ports and the ACT option is activated in PPMS NOTE MultiVu Refer to chapter 2 to install and activate the ACT option ACT measurements may run in immediate mode or sequence mode AC Transport control center commands and PPMS MultiVu Measure menu commands execute measurements immediately but each control center or menu command must be selected manually ACT measurement sequence commands included in a PPMS MultiVu sequence file are executed automatically when they are read while the sequence runs Any number of measurement sequence commands may be included in a sequence file Data from immediate mode measurements is saved only if an ACT measurement data file is selected to store the data and once the measurement is complete the Save button in the measurement dialog box is selected prompting the system to save the data to the specified file Measurement and selected system data read during sequence mode measurements is automatically saved to the specified data file By default when an ACT sequence measurement runs the general system status system temperature magnetic field sample position and the reading from mappable channel 23 are saved to the data file An immediate mode measurement can measure only one sample on the sample puck although you may select which sample you want to
33. See Constant current mode Low impedance mode Electrical interconnections tables for ACT Helium 3 probe cable 6 5 ACT Horizontal Rotator probe cable 7 5 ACT system A 3 A 5 A 6 Electrical transport current measurements See ACT measurements Error messages listed B 2 B 3 recorded in ACT status log 4 7 shown in AC Transport control center 4 2 B 2 Fixed range gain setting definition of 3 3 Gain ranging mode for critical current measurement 5 11 Gain settings 3 3 3 4 Hall coefficient measurement calculating Hall coefficient description of 1 3 1 4 5 7 comparing four wire and five wire 1 4 1 5 copper sample C 1 harmonic detection in 1 5 operating modes 4 1 5 3 parameters defining 5 6 5 7 sample property information affecting 4 8 4 9 saving data from 5 3 5 5 5 8 5 14 taking five wire in immediate mode 5 5 5 7 in sequence mode 5 12 5 15 varying field to perform highly accurate 1 4 wiring sample for on ACT sample puck 1 4 1 5 5 1 5 2 See also Sample wiring Standard PPMS sample puck Index 2 PPMS AC Transport Option User s Manual Rev D 1 Hall potential definition of 1 3 Hardware self test 4 6 Helium 3 refrigerator probe proper handling of 6 2 Helium 3 Refrigerator System option activating in PPMS MultiVu 6 3 6 4 current output limit for 3 3 6 1 6 4 extending measurement range 6 1 6 4 restricting measurements to single sample 6 1 taking ACT measurements when in
34. a tib miii Resistivity dialog box figure 5 8 and then select the data items you Sample 1 Sample2 PPMS Data want to save to the measurement v General Status Brg Ch 1 Resistance I Map 20 data file By default the general IV Temperature Brg Ch 1 Excitation T Map 21 system status system temperature v Magnetic Field Brg Ch 2 Resistance I Map 22 IV Sample Position Brg Ch 2 Excitation IV Map 23 magnetic field sample position and the reading from mappable Sample Pressure Brg Ch 3 Resistance I Map 24 channel 23 user thermometer are 9 o iboen Esaten LI d to the data fil DrCh Curent f BrgCh 4 Resistance Map 26 Savec TEE aaa ne IT DrCh l Power Brg Ch 4 Excitation Map 2 DrCh 2 Curent SigCh 1 Input Voltage Map 28 I DrCh 2 Power Sig Ch 2 Input Volage Map 23 3 Select OK The Resistivity command is added to the sequence 4 Select the Save Sequence File button in Cancel Heb the PPMS MultiVu tool bar Re name the sequence if you like Figure 5 8 PPMS Data Tab in Dialog Box for Defining Resistivity Measurement in Sequence Mode 5 3 52 PREPARE FOR THE MEASUREMENT 1 Mount the sample on a sample puck and connect the sample leads so that you can perform a four wire resistivity measurement Refer to section 5 2 2 Insert the sample into the sample chamber Select the Install tab in the AC Transport control center and then follow the software prom
35. agnostic plot of the measurement in the Waveform tab This plot shows you whether the sample was read and roughly indicates how effective the measurement was Select the Save button if you want to save the results of the measurement to the specified data file or files You must select Save in order to save the data Taking Five Wire Hall Measurements in Immediate Mode 5 3 2 1 PREPARE FOR THE MEASUREMENT 1 Mount the sample on a sample puck and connect the sample leads so that you can perform a five wire Hall coefficient measurement Refer to section 5 2 A thin copper sample is provided for demonstrating the Hall effect see Appendix C for more details Insert the sample into the sample chamber Select the Install tab in the AC Transport control center and then follow the software prompts Select the Data File tab in the AC Transport control center The tab indicates which data files are selected to save the measurement data Click on Browse to select a different file or create a new file see section 4 4 1 If you run the measurement when no data file is selected the data is discarded PPMS AC Transport Option User s Manual Rev D 1 5 5 October 15 2003 Section 5 3 ACT Measurements Chapter 5 Measurements 5 3 2 2 NULL THE OFFSET VOLTAGE Prior to performing any five wire Hall coefficient measurement you null the offset between the nega tive and positive voltage leads You use the Balance potentiometers on the fro
36. ample 1 Tab in Dialog Box for Defining Hall Coefficient Measurement in Sequence Mode 3 4 e Select the PPMS Data tab in the Hall Coefficient dialog box and then select the data items you want to save to the measurement data file By default the general system status system temperature magnetic field sample position and the reading from mappable channel 23 user thermometer are saved to the data file The appearance of the PPMS Data tab in all the ACT sequence measurement dialog boxes is identical Figure 5 8 illustrates the PPMS Data tab in the Resistivity dialog box Select OK The Hall Coefficient command is added to the sequence Select the Save Sequence File button in the PPMS MultiVu tool bar Re name the sequence if you like 5 3 6 2 PREPARE FOR THE MEASUREMENT 1 Mount the sample on a sample puck and connect the sample leads so that you can perform a five wire Hall coefficient measurement Refer to section 5 2 Insert the sample into the sample chamber Select the Install tab in the AC Transport control center and then follow the software prompts Select the Data File tab in the AC Transport control center The tab indicates which data files are selected to save the measurement data Click on Browse to select a different file or create a new file see section 4 4 1 If a data file is selected sequence measurement data is automatically saved to that file If no data file is selected the sequence will not start 5
37. and displays a diagnostic plot of the measurement The Status panel in the control center summa rizes the measurement results The Hall Coefficient dialog box displays the results from the last Hall coefficient measurement as well as the average temperature magnetic field and sample position used during the measurement 2 Examine the diagnostic plot of the measurement in the Waveform tab This plot shows you whether the sample was read and roughly indicates how effective the measurement was 3 Select the Save button if you want to save the results of the measurement to the specified data file or files You must select Save in order to save the data 5 3 3 Taking I V Curve Measurements in Immediate Mode 5 3 3 1 PREPARE FOR THE MEASUREMENT 1 Mount the sample on a sample puck and connect the sample leads so that you can perform a four wire resistivity measurement Refer to section 5 2 2 Insert the sample into the sample chamber Select the Install tab in the AC Transport control center and then follow the software prompts 3 Select the Data File tab in the AC Transport control center The tab indicates which data files are selected to save the measurement data Click on Browse to select a different file or create a new file see section 4 4 1 If you run the measurement when no data file is selected the data is discarded 5 3 32 DEFINE THE MEASUREMENT 1 Select the IV Curve button in the AC Transport control center The I V Curv
38. anels in the Data File tab indicate which data files are selected to save measurement data If no data file has been selected these two panels are blank Measurement data is saved only if a measurement data file is selected Select the Browse button The AC Transport Select Data File dialog box opens The dialog box lists all existing data files Select the drive and directory where the new data files will reside if necessary The default directory to which PPMS MultiVu writes data files is C OdPpms Data Use the File name text box in the AC Transport Select Data File dialog box to enter the name of the new data file If you enter the name of an existing data file or double click on an existing file that file will be overwritten Select Open A pop up message tells you that you must define the sample properties in order to create the data file Select OK in the pop up message The Sample 1 tab in the AC Transport control center opens and all data entry fields in the tab are enabled Figure 4 3 illustrates the Sample 1 tab Enter the sample property information in the appropriate tab or tabs Enter information in the Sample 1 tab if the sample is wired to channel 1 on the Model 7100 AC Transport Controller Enter information in the Sample 2 tab if the sample is wired to channel 2 Use the Next and Back buttons to move back and forth between the two Sample tabs a Use the Material text box to define the sample material The sample materia
39. angle sample chamber pressure mappable channel 23 for a user thermometer and relevant values corresponding to the measurement such as excitation amplitude frequency Hall coefficient resistivity and so on Subsequently changing samples without changing data files can destroy the validity of the data in the file Therefore you are encouraged to use the automated sample installation routine that is activated in the Install tab of the AC Transport control center The automated installation routine prompts you for new data file s and new sample information after you install a new sample One data file can store data from any number of the four measurement types supported by the ACT option However reading a file containing data from multiple types of measurements can be difficult The Physical Property Measurement System PPMS MultiVu Application User s Manual discusses the data file format in detail Data files may be viewed in several different formats The Physical Property Measurement System PPMS MultiVu Application User s Manual discusses the data viewing formats in detail PPMS AC Transport Option User s Manual Rev D 1 Quantum Design October 15 2003 Chapter 4 Software 4 4 1 NOT Caution Quantum Design Section 4 4 ACT Data Files Creating an ACT Measurement Data File 1 Select the Data File tab in the AC Transport control center Figure 4 2 illustrates the tab The File Name and Capture Raw Data p
40. asurement Commands group in the sequence command bar and define the command as follows e Select the Sample 1 tab in the IV Curve dialog box figure 5 10 to set the measurement parameters for a sample wired to channel 1 on the Model 7100 Verify that the Measure check box is selected so that the sample is measured Then set the parameters as necessary Refer to section 5 3 3 2 to review how to set the parameters e Select the Sample 2 tab in the IV Curve dialog box to set the measurement parameters for a sample wired to channel 2 on the Model 7100 Verify that the Measure check box is selected so that the sample is measured Then set the parameters as necessary Refer to section 5 3 3 2 to review how to set the parameters Notice that one sequence measurement can measure two samples The system measures sample 1 then it measures sample 2 PPMS AC Transport Option User s Manual Rev D 1 Quantum Design October 15 2003 Chapter 5 Measurements Section 5 3 ACT Measurements ACT I Curve Ea Sample 1 Sample 2 PPMS Data i i u Select Start and End Current Limit om mA Quadrant CaN Power Limit p mw oints Per 32 Voltage Limit fo m mach noo sh Settling Time os ms IV Constant Current Mode Step Period p ine IV Remove Voltage Offsets Always Autorange Sieg Dunstan 21 333 ma Sticky Autorange PV ad C Fixed Gain Cancel Help Figure 5 10 Sample 1 Tab in Dialog Box for Defining l V Curve Measu
41. be driven through the sample the current output is shut off the mea surement is aborted the Voltage Limited LED on the Model 7100 front panel is lit and an error message is displayed This can occur when the requested current is too high to be driven through the sample resistance and often indicates that the measurement circuit is open infinite resistance If the system s thermal limit is reached the current output is shut off the measurement is aborted the Voltage Limited LED flashes and an error message is displayed The LED remains flashing until the current drive amplifiers in the Model 7100 cool to an acceptable level The built in thermal limit protects the sample and the ACT drive electronics Output Range Table 3 1 Model 7100 Drive Source Impedance in Low Impedance Mode To optimize system performance the Model 7100 automatically selects the current range for the sample excitation The drive source impedance is very high OUTPUT NOMINAL DRIVE gt 10 MQ in constant current mode In low impedance mode however the drive source impedance depends RANGE SOURCE IMPEDANCE on the output range as shown in table 3 1 200 pA 100 KQ The LEDs in the Output Range area of the Model 7100 2mA 10kQ front panel indicate which range the controller is using When no range LED is lit the Model 7100 is not out 20 mA 1kQ putting current Notice that when the PPMS Helium 3 Refrigerator option is ins
42. ber and the Helium 3 and ACT software applications are running you may take ACT measurements at temperatures as low as 0 4 K You take ACT measurements and write sequences according to the usual procedures described in section 5 3 Note however that when the refrigerator probe is installed the ACT current output is limited to 20 mA or less 6 4 PPMS AC Transport Option User s Manual Rev D 1 Quantum Design October 15 2003 Chapter 6 Section 6 4 Operation with the Helium 3 System Interconnection Tables for the ACT Helium 3 Probe Cable 6 4 Interconnection Tables for the ACT Helium 3 Probe Cable Table 6 1 Pin Mapping for Helium 3 Thermometer Wiring GRAY LEMO FOUR PIN LEMO HELIUM 3 CONNECTOR ON CONNECTOR AT P1 SAMPLE MOUNT PROBE HEAD PORT ON MODEL 6000 FUNCTION No Connection 11 1 Helium 3 Therm I No Connection 12 2 Helium 3 Therm I No Connection 13 3 Helium 3 Therm V No Connection 14 4 Helium 3 Therm V Table 6 2 Pin Mapping for ACT Drive Current Wiring GRAY LEMO HELIUM 3 CONNECTOR ON P1 PORT ON SAMPLE MOUNT PROBE HEAD MODEL 7100 FUNCTION 7 7 1 4 ACT Chl Ch2 I 8 8 6 9 ACT Ch1 Ch2 I Table 6 3 Pin Mapping for ACT Voltage Readback Wiring GRAY LEMO HELIUM 3 CONNECTOR ON P5 PORT ON SAMPLE MOUNT PROBE HEAD MODEL 7100 FUNCTION 9 9 5 amp 7 Ch2 Va b 10 10 6 amp 8 Ch2 V 3 3 3 Chl Vb 4 4 4 Chi V 5 5 2 Chi V 6 6 1 Chl Var
43. cal Current Measurement in Sequence Mode 5 18 Figure 6 1 ACT Helium 3 Probe Cable nude mne ato UR ae Teen 6 2 Figure 6 2 Sample Wiring Diagrams for the Helium 3 Option eese nennen nennen enne enne 6 3 Figure 7 1 ACT Horizontal Rotator Probe Cable sese enne nennen nennen trennen enne 7 2 Figure 7 2 Sample Wiring Diagrams for the Horizontal Rotator Option eere 7 4 Fig r A N ACT Connections ieena ORI Attn pad ian A 1 Figure A 2 Rear Panel on Model 7100 AC Transport Controller eese eene eene A 2 Figure A 3 Illustration of ACT Sample Connections rennen ennt enne A 4 Figure C 1 Copper Sample for Verifying the Hall Effect Measurement sese C 1 iv PPMS AC Transport Option User s Manual Rev D 1 Quantum Design October 15 2003 Contents Table of Tables Table 3 1 Model 7100 Drive Source Impedance in Low Impedance Mode eee 3 3 Table 3 2 Voltage Detection Gain Stages eene nee nnen enne trennen innen enne tenerent teen 3 4 Table 4 1 Software Files Required to Operate ACT Option sese enne 4 1 Table 6 1 Pin Mapping for Helium 3 Thermometer Wiring eese enne enne eene enne 6 5 Table 6 2 Pin Mapping for ACT Drive Current Wiring eeeeeeeseeeeeeeeee eene enne enne rennen eren ener ennt 6 5 Table 6 3 Pin Mapping for ACT Voltage Readback Wiring eeeeeeeeeeeeee
44. ct 00001 log C0 x 43755881 48 AC Transport started at 5 26 33 10 24 41 4M 43755881 54 AC Transport Calibration file serial None 43755883 77 Resistivity 43755890 10 Autoranging 43755830 10 Good Gain at 5000mv Range poem 32 Measure complete Good Gain at 5000m Range Figure 4 6 ACT Status Log Quantum Design PPMS AC Transport Option User s Manual Rev D 1 4 7 October 15 2003 Section 4 4 ACT Data Files 4 4 4 8 Chapter 4 Software ACT Data Files The ACT software creates measurement data files and raw measurement data files and stores ACT measurement data in these files Measurement data files store sample measurement data for any number of measurements taken by any of the measurement types supported by the ACT option Raw measurement data files store raw voltage data for every measurement taken while the raw file is selected Measurement data files have a dat file extension Raw measurement data files have a raw extension Each raw measurement data file is associated with one measurement data file and uses the identical base name as the measurement data file Sample measurement data is saved only if a measurement data file is selected Raw voltage data is saved only if a measurement data file is selected and the software is prompted to capture raw voltage data Data is saved to only the selected data file or files The Data File tab in the AC Transport control center indicates which data file or files
45. ction of each electrical port on the rear panel of the Model 7100 AC Transport Controller Chapter 3 discusses the monitor outputs on the front panel of the Model 7100 amp e e IWTERPACE www ww cuen or 90 ea OFFSET Ay CUOR Abu Figure A 2 Rear Panel on Model 7100 AC Transport Controller Table A 1 Electrical Ports on Model 7100 Rear Panel PORT FUNCTION P1 Sample Current Out Provides current excitation for sample Y cable is used to connect port to gray Lemo connector on probe head Opposite end of Y cable connects to P5 port on Model 7100 P2 Drive Access and Monitor For monitoring current through sample and normally contains set of jumpers Removing jumpers allows ammeters to be inserted into circuit but breaks drive circuit open essentially disabling system completely if circuit is not completed in some other manner One pin on P2 port is reserved to allow synchronization of other instruments with the excitation signal This capability is for future development P3 Analog Interface 15 pin D connector that sends detected sample signal to AC board in Model 6000 so signal can be digitized and recorded P3 port is connected to P3 port on Model 6000 P4 Digital Interface 9 pin D connector that is input for digital signals from AC board in Model 6000 These signals are amplified to provide excitation signal for sample P4 port is connected to P3 por
46. drive electronics cool down and or allow more time between measurements PPMS AC Transport Option User s Manual Rev D 1 October 15 2003 Quantum Design Appendix B Section B 3 Error and Warning Messages Error Messages ERROR EXPLANATION POSSIBLE SOLUTIONS e GPIB error Hardware or communication e GPIB cable not connected Exception type warnings e DSP checksum error e DSP frame read error e DSP not responding e DSP send error failure Check GPIB cable connec tion from PC to Model 6000 e DSP on AC board failed after encountering unexpected situation Contact Quantum Design ACT calibration file error Calibration file has invalid data Calibration file is corrupt or has been moved or renamed Verify that file C OdPpms ACTrans Calibration Actcal cfg contains valid calibration data and correct serial numbers Quantum Design PPMS AC Transport Option User s Manual Rev D 1 October 15 2003 A P PEN DIX C Measuring the Hall Coefficient of the Copper Hall Sample C 1 C 2 Introduction This appendix contains the following information e Section C 2 discusses measuring the Hall coefficient of the copper Hall effect standard to verify the operation of the AC Transport Option Verifying the Hall Effect Measurement The AC Transport option is provided with a thin copper sample Figure C 1 gt that can be used to verify the operation m of t
47. e 5x mi dB mm ps I o Measure Save Close Help Figure 5 4 Dialog Box for Defining Hall Coefficient Measurement in Immediate Mode Use the Amplitude text box to specify a small current in milliamperes that will not harm the sample The current is the amplitude of the sine wave excitation applied to the sample The Model 7100 provides as much as 2 A of current This large current can damage samples and other equipment in the current path Use only currents that can be safely handled by all hardware and samples in the circuit Use the Frequency text box to specify a frequency in hertz for the sample excitation signal Avoid integer multiples of the power line frequency Use the Duration text box to specify the time in seconds over which the ACT will measure the voltage across the sample Verify that the Constant Current Mode check box is enabled if you want the Model 7100 to operate in constant current mode Disable the check box only to make the Model 7100 operate in low impedance mode In constant current mode the Model 7100 adjusts the potential drop across the current leads in order to maintain a desired current through the sample regardless of sample resistance see section 3 2 1 Enable the Small Coefficients Mode check box only if the sample has a Hall resistance less than approximately 1 uQ and you want to reduce the compliance voltage at the current driver by a factor of 10 in order to provide a more sym
48. e C QdPpms Actrans System Actrans dll Actransport reg License txt Readme txt C QdPpms Actrans Calibration Actcal cfg C QdPpms Actrans Logfiles ActStatus log C QdPpms MultiVu ActOption dll Quantum Design PPMS AC Transport Option User s Manual Rev D 1 4 1 October 15 2003 Section 4 2 Chapter 4 Overview of the ACT Software Software 4 2 1 4 2 The calibration file for the ACT option contains specific calibration information pertaining to the serialized AC board ACT preamp board and ACT driver board During start up the serial numbers are shown in the Status bar in the AC Transport control center see section 4 2 1 and should match the actual serial numbers on the system hardware AC Transport Control Center The ACT software includes a control center The AC Transport control center opens as soon as the ACT option is activated and does not close until the option is deactivated The AC Transport control center makes basic system operations such as installing samples creating data files and setting up and running immediate mode measurements more natural and convenient The control center includes all frequently selected ACT commands Software prompts and an easy to use tab format simplify data file creation Figures 4 1 through 4 5 illustrate the six tabs in the control center The Status bar at the bottom of the AC Transport control center summarizes the general status of the ACT system The
49. e dialog box for an immediate mode measurement opens 5 8 PPMS AC Transport Option User s Manual Rev D 1 Quantum Design October 15 2003 Chapter 5 Measurements 2 Caution 3 4 5 6 Ty Quantum Design Section 5 3 ACT Measurements ACT I Curve Ic x Excitation Start and End Quadrant 7 Euren Umi o m Power Limit o mw Voltage Limit o my Settings 7 IV Constant Current Mode Settling Time h ms IV Remove Voltage Offsets Step Period E Hem Always Autorange C Sticky Autorange Step Duration 55 333 ms C Fixed Range E z oints Per 22 X i Last eke 3 uadrant i o Total Time 3382 sec Temp K i roo00 Select Channel Field Oe Sample 1 C Sample2 Position jao deg Measure Save Close Help Figure 5 5 Dialog Box for Defining l V Curve Measurement in Immediate Mode Use the Current Limit text box to specify the maximum current in milliamperes for the ramp The Model 7100 provides as much as 2 A of current This large current can damage samples and other equipment in the current path Use only currents that can be safely handled by all hardware and samples in the circuit Use the Power Limit text box to specify an approximate power limit in milliwatts The power limit is intended to protect the sample and is not a tool for precision measurement purposes and it is calibrated with this in mind A power limit may not b
50. e screws Notice the small gap between the Model 6000 and the Model 7100 to allow air flow mi You should also install the Masonite blank panel included with the ACT 3 installation kit if you have an older PPMS electronics cabinet Use the NOTE four remaining screws to hold the Masonite blank panel in place Quantum Design PPMS AC Transport Option User s Manual Rev D 1 2 5 October 15 2003 Section 2 3 Chapter 2 Installation Procedures Installation 2 3 3 Connect the System 1 Complete the electrical connections for the ACT option as shown in figure 2 4 Make certain that you screw all connectors solidly into place A special four way cable not shown in figure 2 4 supplied with the PPMS rotator options or the Helium 3 option is necessary only when one of these options is used with the ACT system MODEL 6000 I 3084 513 3 S e P4 DIGITAL P3 ANALOG P2 DRIVE ACCESS P1 SAMPLE INTERFACE INTERFACE AND MONITOR CURRENT OUT 5 I de gt O e uo qap Gayo a MODEL 7100 NN 3084 516 3084 511 Figure 2 4 ACT Connections 2 Install the 15 pin D shell connector labeled P2 Current Breakout into the P2 Drive Access and Monitor port on the rear of the Model 7100 The ACT system is disabled when no connec tion is made at the P2 port so verify that the
51. e set when low impedance mode is used Refer to step 10 Use the Voltage Limit text box to specify an approximate voltage limit in millivolts The voltage limit is intended to protect the sample and not be a tool for precision measurement purposes and is calibrated with this in mind Specify the settling time in milliseconds the software waits at each small step of the current ramp before measuring and averaging the voltage drop for the remainder of the step period Specify the step period in number of power line cycles in order to determine the length of time spent measuring at each small step of the current ramp The time required for each step of the ramp is calculated from the power line frequency and the step period and is reported as the Step Duration Use the Points Per Quadrant pull down menu to select the number of points recorded for each section of the ramp pattern Up to 256 points may be recorded for a one quadrant section up to 128 points for a two quadrant section and up to 64 points for a three or four quadrant section Select the sample Sample 1 or Sample 2 you want to measure Click and drag the mouse through the Start and End Quadrant panel to select the starting and ending quadrants for the ramp pattern The pattern may begin and end at the positive or negative peak value or at zero current The starting and ending points appear in green on color monitors As you select the ramp pattern the value in the Tota
52. e the cause of the problem before you use the system to perform any other operations If the error message indicates a software problem you should restart PPMS MultiVu and reactivate the ACT option ERROR Data read binary check sum DSP error EXPLANATION Data was corrupted when read by DSP or when sent to PC by Model 6000 POSSIBLE SOLUTIONS DSP has possible problem Restart Model 6000 GPIB connection or setup has problem Check cables or examine setup in PC control panel System may have malfunc tioning DSP card or other hardware problem Contact Quantum Design if problem persists Thermal or compliance voltage error Excess power consumption condition detected Either excitation is too high or sample is not properly connected Model 7100 power is off Turn on Model 7100 power System connections are incomplete Check system connections Model 7100 rear panel drive access is open Check for jumpers on P2 port Model 7100 internal connec tions are loose or undone Check internal ribbon cables Sample wiring has become disconnected Check sample Sample resistance is too high Adjust environmental and measurement parameters Model 7100 has blown its fuse Check fuse and replace only with equivalent 1 A 110 V or 0 5 A 220 V fuse Thermal cutoff adjust on rear of Model 7100 has been turned down Turn pot up Too many high current mea surements are made in a row Let
53. ect the sample leads so that you can perform a four wire resistivity measurement Refer to section 5 2 Insert the sample into the sample chamber Select the Install tab in the AC Transport control center and then follow the software prompts PPMS AC Transport Option User s Manual Rev D 1 Quantum Design October 15 2003 Chapter 5 Measurements Section 5 3 ACT Measurements Select the Data File tab in the AC Transport control center The tab indicates which data files are selected to save the measurement data Click on Browse to select a different file or create a new file see section 4 4 1 If you run the measurement when no data file is selected the data is discarded 5 3 4 2 DEFINE THE MEASUREMENT 1 Caution Quantum Design Select the Critical Current button in the AC Transport control center The Critical Current dialog box for an immediate mode measurement opens Items in the upper part of the dialog box designate measurement conditions that should be set prior to selecting the Measure button Items in the lower part of the dialog display the results of the last critical current measurement ACT Critical Current icd x Excitation Last Measure Max Current fi 0 m Temp K Critical Votage E mV Field Oe Power Limit 100 mw Posion de ReCoolTime 1 Sec Hanging Averaging Time Line z V Limited 0 v e Measures h 7 fus Critical Current ma sane pe n p pgs uu C
54. eha 4 1 4 2 1 AC Transport Control Center sessie oriri Renee e be ene eb eed ie iet eee 4 2 4 2 1 1 Install Tab tec ete ten Boa Si ENG AM a Bikol 4 2 4 2 1 2 Data Eile Tab eror ete eed uttter oma 4 3 AD AS Sample TADS ice tot ente ee ee e etd e ipte dt et e ie ey 4 4 4 2 1 4 Waveform Tab ie be ar ne EUR REDE ERE EP 4 5 4 2 1 5 Configure Tab 525 a e B PR E RCS ga EN de hais ach ah pas shos he E EE E EEE 4 6 4 2 1 6 Measurement Command Buttons eese teen enne enne enne ennt tenete trennen 4 6 4 33 ACT Status Log e eot he Ge tee pep iP OL e er E OREL ee Re Rr Spe RR 4 7 44 ACT Data Eil s Hc PEL 4 8 4 4 1 Creating an ACT Measurement Data File esee ener enne ener nenne tnne nennen 4 0 CHAPTER 5 Measurements 4o soo eic ee oe ane es C e Deb deed 5 1 5 I Introduction 5s ena te epe cite a eite dete crt d tede eb n EU eda nies Abs 5 1 5 2 Sampl Mounting Procedures 4a etra eet are eit adu ee e RU RR ERE reos 5 1 5 2 ACT Measurements ee OI ee NIB ipaa reete bietet 5 3 5 3 1 Taking Resistivity Measurements in Immediate Mode essere 5 3 5 3 1T Prepare for the Measurement ox cesses hei eee itd ede det tede er ted ie 5 3 5 3 1 2 Define th M easement s s oc chier tee e tede dei i ee tied 5 4 3 3 1 3 Run the Measurement e ete nee ivre or erp rent esie mr iiy erede E EEEE 5 5 5 3 2 Taking Five Wire Hall Measurements in Immediate Mode esee 5 5 5 332 T
55. ement you may also specify an averaging time of one power line cycle in which case the response time depends on the line frequency The power line cycle setting has the longest response time Quantum Design PPMS AC Transport Option User s Manual Rev D 1 1 7 October 15 2003 C H APTER 2 Installation 2 1 2 2 Quantum Design Introduction This chapter contains the following information Section 2 2 lists the components in the e Section 2 3 explains how to install the ACT installation kit ACT option If your PPMS was ordered with the ACT option the ACT hardware and software were installed at the factory You do not need to refer to these installation instructions Installation Kit Components The ACT installation kit contains the following items ral ral KKK KKK Model 7100 AC Transport Controller AC board with two 3 8 in screws four 3 16 in nuts four 3 16 in lock washers and one ribbon cable Three connection cables one 9 pin cable one 15 pin cable and one Y cable 15 pin D shell connector with two jumpers inserted in it Power cord 44 7 cm x 48 3 cm 17 6 in x 19 in Masonite blank panel for older PPMS cabinets Three ACT sample pucks with mounting circuit boards Overlay for PPMS desktop puck box 90 mm 3 5 in disks containing necessary software and calibration files Contact Quantum Design if any of these items are missing from the installation kit PPMS AC Transport Option User
56. ene enne nne eene enne 6 5 Table 7 1 Pin Mapping for P2 System Bridge Port on Model 6000 sese 7 5 Table 7 2 Pin Mapping for P1 Sample Current Out Port on Model 7100 esee 7 5 Table 7 3 Pin Mapping for P5 Sample Voltage In Port on Model 7100 sse 7 5 Table A 1 Electrical Ports on Model 7100 Rear Panel eese enne emeret enne A 2 Table A 2 Connections from Sample to Model 7100 00 cee eessecssesecseeseceeeeeceseeecesecseesecnavsecsaeseeseesaeeeceaeeseenaeeeeeas A 3 Table A 3 Drive Access and Monitor Connections eese eene ener enne ene tnen rennen innen e nnne A 5 Table A 4 Connections between P3 Analog Interface Port and P3 Option Port sse A 6 Table A 5 Connections between P4 Digital Interface Port and P3 Option Port eee A 6 Quantum Design PPMS AC Transport Option User s Manual Rev D 1 V October 15 2003 P RE FA C E Contents and Conventions P 1 Introduction This preface contains the following information e Section P2 discusses the overall scope e Section P 4 illustrates and describes of the manual conventions that appear in the manual e Section P 3 briefly summarizes the contents of the manual P 2 Scope of the Manual This manual discusses the operation of the AC Transport Measurement System ACT option hardware and software and explains how to take ACT measurements This manua
57. es in the circuit Electrical Current Operating Modes The Model 7100 can operate in either constant current mode or low impedance mode Figure 3 2 compares the behavior of the current in both modes Constant current or high impedance mode is the default operating mode and the preferred mode for most applications In constant current mode the Model 7100 adjusts the potential drop across the current leads in order to maintain a desired current through the sample regardless of sample resistance The Constant Current LED on the Model 7100 front panel is lit when the unit operates in constant current mode The Model 7100 is not a perfect current source when it operates in low impedance mode The avail able current decreases with the increasing potential drop across the current leads and the actual current equals the requested current only when the sample resistance is very low compared to the Model 7100 current drive source impedance Low impedance mode is useful when an I V curve might be multiple valued in I Vi V V Figure 3 2 The available current as a function of voltage drop across the current leads The dashed lines indicate how the current behaves when the current setting is changed PPMS AC Transport Option User s Manual Rev D 1 Quantum Design October 15 2003 Chapter 3 Hardware 3 2 2 3 2 3 Ouantum Design Section 3 2 Model 7100 AC Transport Controller If the requested current cannot
58. es with the magnetic field When charged particles move perpendicular to a magnetic field a force is exerted on them perpendic ular to both the field and the direction of particle motion F qv x B Equation 1 2 Therefore if a transverse current is passed through a sample in a longitudinal magnetic field charge carriers often build up on one edge of the sample and disappear from the other edge leading to a potential difference across the sample figure 1 3 This potential difference is the Hall potential The sign of the Hall potential generally indicates whether a conductor is N type or P type and the magnitude of the Hall potential is related to the density of charge carriers in the sample The Hall coefficient R describes these two properties and is defined by me p E is Equation 1 3 where E is the Hall field V is the Hall potential j is the current density given by A which is the current divided by the sample cross section and is the separation of the transverse voltage leads It can be shown that R nq with n representing the number of charge carriers per unit volume in the sample and q representing the charge of the carriers The ACT option reports Hall coefficients in units you can configure Quantum Design PPMS AC Transport Option User s Manual Rev D 1 1 3 October 15 2003 Section 1 3 Chapter 1 ACT Measurement Types Theory of Operation V Figure 1 3 Four Wire Hall Effect Measurement for Sample
59. etting is selected Sticky Autorange prevents the system from changing gains until absolutely necessary Fixed Range restricts the system to the use of a single user specified gain setting Select the sample Sample 1 or Sample 2 you want to measure 5 3 1 3 RUN THE MEASUREMENT 1 Select the Measure button The measurement begins The Measure button now reads Cancel You select Cancel to abort the measurement To measure resistivity the designated alternating current is driven through the appropriate channel for the specified duration The Model 7100 preamp board amplifies the detected voltage signal before it is sampled by the digital signal processor on the AC board and analyzed by the software The sample resistivity is calculated with equation 1 1 The Status panel at the bottom of the AC Transport control center indicates the status of the on going measurement The system temperature magnetic field and sample position are measured at the beginning and end of the resistivity measurement and their average values are reported As soon as the measurement is complete the Waveform tab in the control center opens and displays a diagnostic plot of the measurement The Status panel in the control center summa rizes the measurement results The Resistivity dialog box displays the results from the last resistivity measurement as well as the average temperature magnetic field and sample position used during the measurement Examine the di
60. ev D 1 October 15 2003 Quantum Design Ouantum Design Operation with the Horizontal Rotator Interconnection Tables for the ACT Horizontal Rotator Probe Cable Interconnection Tables for the ACT Horizontal Rotator Probe Cable Table 7 1 Pin Mapping for P2 System Bridge Port on Model 6000 GRAY LEMO FOUR PIN LEMO SAMPLE HOLDER CONNECTOR ON CONNECTOR AT P2 BOARD PROBE HEAD PORT ON MODEL 6000 FUNCTION 3 3 1 Bridge Ch4 I Rotator Therm Bridge Ch4 I j Rotator Therm 5 5 3 Bridge Ch4 V Rotator Therm Bridge Ch4 V d 2 4 Rotator Therm Table 7 2 Pin Mapping for P1 Sample Current Out Port on Model 7100 GRAY LEMO SAMPLE HOLDER CONNECTOR ON P1 PORT ON BOARD PROBE HEAD MODEL 7100 FUNCTION T 7 1 4 ACT Chl Ch2 I 8 8 6 9 ACT Ch1 Ch2 I Denoted leads on the Horizontal Rotator are a copper alloy while the remainder of the leads on the Rotator are phosphor bronze Table 7 3 Pin Mapping for P5 Sample Voltage In Port on Model 7100 GRAY LEMO SAMPLE HOLDER CONNECTOR ON P5 PORT ON BOARD PROBE HEAD MODEL 7100 FUNCTION 9 9 5 amp 7 Ch2 Va b 10 10 6 amp 8 Ch2 V 11 11 3 Chl Vb 12 12 4 Chi V 13 13 2 Chi V 14 14 1 Chl Va Denoted leads on the Horizontal Rotator are a copper alloy while the remainder of the leads on the Rotator are phosphor bronze PPMS AC Transport Option User s Manual Rev D 1
61. he Hall effect measurement It is shaped for the five wire Hall geometry and conveniently sized so that the ends WA Roy solder directly on top of the I and I pads on the ACT puck The two short qf m side leads solder to V a and Vb pads ys AX the long middle lead bends over the top a of the sample and solders to V see Figure C 1 Copper sample for verifying the Hall also Fig 5 1 effect measurement Important Prevent the long lead from touching the other side of the sample when crossing over it as this would short out the Hall effect The following values can be used for the copper sample geometry Transverse voltage lead separation W 0 25 cm width of sample Longitudinal cross section area A 1 93e cm W thickness Note The transverse lead separation is required for Hall effect measurements After you have nulled the offset voltage see Section 5 3 2 measure the Hall coefficient of the copper sample using 100 mA and 103 Hz as the recommended excitation settings For the best accuracy measure at magnetic fields above 1 tesla The literature value of the Hall coefficient for copper at room temperature is Ry 5 4x 10 cm C Ouantum Design PPMS AC Transport Option User s Manual Rev D 1 C 1 October 15 2003 References Quantum Design 1998 Physical Property Measurement System Hardware Manual 1999 Physical Property Measurement System Helium 3 Refrigerator System User s Manual
62. hether an AC board is installed in the P3 Option slot in the Model 6000 If an AC board is installed remove it as follows a remove the four nuts that hold the AC board to the posts inside the Model 6000 and then b remove the two rear panel screws Refer to figure 2 2 on the following page Lay the new AC board on the posts behind the P3 Option slot Position the board so that the two D shell connectors on the board protrude through the P3 Option port Install the two rear panel screws on either side of the P3 Option port in order to secure the AC board Refer to figure 2 2 Place the four lock washers on the posts and screw the AC board into place by screwing the nuts supplied with the board onto the four posts Use a nut driver or a set of tweezers and needle nose pliers if necessary Connect the ribbon cable from the J3 connector on the AC board to the J15 Options connector on the motherboard The J15 Options connector is just below the AC board Refer to figure 2 2 Connect the red and black power line from the wire bundle underneath the front of the motherboard to the J4 power connector Refer to figure 2 2 Verify that the two EPROMs on the CPU board are dated 3 22 96 or later If the EPROMS are dated earlier than 3 22 96 you must upgrade them before continuing with the ACT installation Service note 1070 802 PPMS Software and Firmware Upgrade Instructions explains how
63. ion is selected and the Auto Check on Startup option is not selected The results of the most recent hardware self test are summarized in the Test Results field During a hardware self test the ACT status log is displayed figure 4 6 Details of the test are also listed in the ACT status log and recorded in the log file The Settings panel in the Configure tab includes a configurable critical current hard trip parameter which is a parameter for critical current measurements You use the parameter to set an absolute cutoff voltage that is the sum of the critical current voltage limit plus a percentage of the full scale voltage Setting an absolute cutoff voltage is useful to protect the sample under some experimental conditions For example the critical current measurement checks the voltage across the sample at the beginning of the measurement and subtracts this value from subsequent readings as it increases the current to remove any voltage offset from the final result If for some reason the voltage across the sample is very large before the measurement begins the hard trip setting helps protect the sample by cutting off the current The critical current hard trip is a percentage from 0 to 100 with the default being 20 The specified value is remembered between ACT sessions The diagnostic mode accessed through the Diagnostic button in the Configure tab is password protected and is used only by service personnel 4 2 1 6 MEASUREMENT COMMAND
64. itle Emea fac Transport Datafile Hall Coefficient Resistivity IV Curve Critical Current Hall Coefficient Resistivity IV Curve Critical Current Status fac Transport Calibration file serial None Status fac Transport Calibration file serial tt None A Sample 1 Tab B Sample 2 Tab AC Transport Datafile Figure 4 3 Sample Tabs in AC Transport Control Center In the Sample 1 and Sample 2 tabs you define the sample property information which is the sample material as well as the sample s voltage lead separation and cross sectional area and you enter any comment you want to include in the data file header You can also specify the title of the graph view of the data file The sample property information and any user comments are written to the header of the new measurement data file Once you create the file you cannot change any information written to the data file header Selecting the Finish button in the Sample 2 tab creates the file and writes the header If you are uncertain what values to use for the voltage lead separation and cross sectional area use the default value of 1 A value of 1 does not affect the accuracy of the data PPMS AC Transport Option User s Manual Rev D 1 Quantum Design October 15 2003 Chapter 4 Section 4 2 Software Overview of the ACT Software 4 2 1 4 WAVEFORM TAB The Waveform tab shows a diagnostic plot of the results of the last measurement The light blue curve in the
65. ive Access and Monitor Port DENT se MODEL 7100 FUNCTION 3x ba 3 SNE NNI m n Iom PPMS AC Transport Option User s Manual Rev D 1 October 15 2003 Section A 4 Pinout Tables A 5 Section A 4 Appendix A Pinout Tables Connections Ports and Pinouts A 4 3 AC Board Connections Table A 4 Connections between P3 Analog Interface Port and P3 Option Port P3 Analog Interface Port on Model 7100 P3 Option Port on Model 6000 18345678 876543 21 oocoeoeevee 969 COOOOCOO ecc ccn OOOOOOO 9 10 11121314 15 151413 121110 9 s os emm s o mem o3 f o me Table A 5 Connections between P4 Digital Interface Port and P3 Option Port P4 Digital Interface Port on P3 Option Port on Model 6000 Model 7100 54321 OOOO 6789 a eT MN 3 L3 ee dde 9 o pea A 6 PPMS AC Transport Option User s Manual Rev D 1 Quantum Design October 15 2003 A PP E NDIX B Error and Warning Messages B 1 Introduction This appendix contains the following information e Section B 2 lists and discusses the ACT e warning messages B 2 Section B 3 lists and discusses the ACT error messages Warning Messages Warning messages appear on a yellow background in the status bar that is at the bottom of the AC Transport control center Warning messages indicate a minor hardware or software problem If a measurement is in progress when a warning message appears the
66. ized calibrated thermometer Quantum Design PPMS AC Transport Option User s Manual Rev D 1 7 3 October 15 2003 Section 7 4 ACT Measurements with the Horizontal Rotator 7 4 Caution E NOTE Chapter 7 Operation with the Horizontal Rotator ACT Measurements with the Horizontal Rotator When the Horizontal Rotator probe is installed in the sample chamber the ACT option can measure Hall coefficients for samples that are wired properly for that measurement type The wiring schemes in figure 7 2 report a positive Hall coefficient if the carriers are hole like and a negative coefficient if the carriers are electron like for samples that are face up in the sample chamber For Horizontal Rotators with serial numbers 001 010 the sample is face up at a 180 orientation Rotators with serial numbers 011 or greater are face upwards with an orientation of 0 or 360 Only two current leads are available Current can be sourced from either channel 1 or channel 2 depending on which channel is active but current is always routed through the I and I solder pads on the ACT sample holder This allows two channels using different drive currents to be used for different measurements To mount two samples on the same sample holder you wire the samples in series on the current leads When making resistance measurements the ACT balance potentiometer that is dedicated to the active channel must be in the full counterclockwise 0 0 posi
67. jumpered connector is installed and screwed securely into place 3 Turnon the Model 7100 2 3 4 Install the Software 1 Install the PPMS MultiVu software if it is not already installed Do the following a insert PPMS MultiVu Disk 1 into the PC b select the A drive c select setup exe and then d complete all operations the InstallShield wizard prompts you to perform The ACT software runs in conjunction with the PPMS MultiVu software PPMS MultiVu must be installed on the host computer in order for the ACT software to work If you try to install the ACT software before you install PPMS MultiVu the InstallShield wizard for the ACT software fails and generates a warning message which tells you to install PPMS MultiVu 2 Install the ACT option software Do the following a insert Disk 1 for the ACT software into the PC b select the A drive c select setup exe and then d complete all operations the InstallShield wizard prompts you to perform 3 Activate the ACT option in PPMS MultiVu Do the following a start up PPMS MultiVu b select Utilities gt Activate Option c click on AC Transport under the Available Options heading and then d select the Activate button As soon as you activate the ACT option the AC Transport control center opens and the Measure menu items and measurement sequence commands that are specific to the ACT option appear in the PPMS MultiVu interface 2 6 PPMS AC Transport Option User s
68. l Time field changes The step duration multiplied by the number of points per quadrant and the number of ramps required by the ramp pattern yields the total time for the I V trace PPMS AC Transport Option User s Manual Rev D 1 5 9 October 15 2003 Section 5 3 ACT Measurements 5 3 4 Caution 5 10 10 11 12 Chapter 5 Measurements Verify that the Constant Current Mode check box is enabled if you want the Model 7100 to operate in constant current mode Disable the check box only to make the Model 7100 operate in low impedance mode In constant current mode the Model 7100 adjusts the potential drop across the current leads in order to maintain a desired current through the sample regardless of sample resistance see section 3 2 1 Verify that the Remove Voltage Offsets check box is enabled if you want the system to measure the input voltage before any current is applied to the sample and then subtract this baseline voltage off of all subsequent readings for the I V trace Select the gain setting used for voltage detection Always Autorange instructs the system to change the gain setting at the beginning of every measurement so that the optimum setting is selected Sticky Autorange prevents the system from changing gains until absolutely necessary Fixed Range restricts the system to the use of a single user specified gain setting 5 3 3 3 RUN THE MEASUREMENT 1 Select the Measure button The measurement begin
69. l does not provide detailed information about the PPMS MultiVu software application which is the software running the Physical Property Measurement System PPMS The ACT option software is integrated into PPMS MultiVu The Physical Property Measurement System PPMS MultiVu Application User s Manual discusses the functionality of PPMS MultiVu P 3 Contents of the Manual e Chapter 1 presents an overview of the e Chapter 6 explains how to use the ACT option and ACT measurements ACT option with the Helium 3 option e Chapter 2 explains how to install the e Chapter 7 explains how to use the ACT option ACT option with the Horizontal Rotator e Chapter 3 discusses the operation of e Appendix A describes and illustrates the ACT hardware the ACT electrical ports e Chapter 4 discusses the ACT software e Appendix B lists error and warning and ACT data files messages e Chapter 5 explains how to mount samples and take ACT measurements Quantum Design PPMS AC Transport Option User s Manual Rev D 1 vu October 15 2003 Section P 4 Conventions in the Manual P 4 Preface Contents and Conventions Conventions in the Manual File menu File gt Open STATUS dat Enter lt Alt Enter gt Ene LE Caution Warning Bold text distinguishes the names of menus options buttons and panels appearing on the PC monitor or on the Model 6000 PPMS Controller LCD screen The gt symbol indicates that you select multiple nested
70. l information is saved in the data file header but is not used to calculate measurement values b Use the Comment text box to enter any comment you want to include in the data file header c Use the Voltage Lead Separation text box to define the sample s voltage lead separation If you are uncertain what the length of the voltage lead separation is use the default value of 1 cm d Use the Cross Section Area text box to define the cross sectional area in the sample through which the current passes If you are uncertain what the cross sectional area is use the default value of 1 cm Always use the default value of 1 if you do not know the actual value of the sample s voltage lead separation or cross sectional area A value of 1 lets the calculated values reflect numbers unadjusted for sample geometry and thus allows easy interpretation of resistivity and Hall coefficient values if sample information is unavailable Defining the correct voltage lead separation and cross sectional area is extremely important because the system uses these values to calculate the sample resistivity and the Hall coefficient Once you create the data file you cannot use the software to redefine any information that was written to the data file header e Use the Datafile Title text box to specify a title for the graph view of the data file if you like Specifying a title for the graph view is not mandatory f Select Next to open the Sample 2 tab
71. ll voltage the sample resistance may still make a contribution to the measured transverse voltage even after balancing the pot You may therefore want to make Hall measurements at positive and negative fields so that the field sympathetic magnetoresistive component can be subtracted from the measured resistivity 1 4 PPMS AC Transport Option User s Manual Rev D 1 Quantum Design October 15 2003 Chapter 1 Section 1 3 Theory of Operation ACT Measurement Types Several notes of caution must be made The ACT option uses 100 2 potentiometers For samples that have resistance on the order of 1 2 up to 1 of the current applied to the sample might pass through the potentiometer This is important to consider because the reported Hall coefficient and resistivity assume a known current through the sample The current through the sample is equal to the applied current only if the sample resistance is much smaller than the 100 Q potentiometer resistance 1 v Vrmeas I j I e e i e e Vt V V Vmeas Vat Vres HE 0 Vmeas Vh IR T H VP Vit V A Offset with a Four Wire Hall B Offset Nulling with a Five Wire Hall Coefficient Measurement Coefficient Measurement Figure 1 4 Leads Attached for Four Wire and Five Wire Hall Coefficient Measurements The ACT option includes many features to prevent induced signals from interfering with measurements For example a second negative
72. lso AC board Installing in illustration of ACT electrical connections 2 6 A 1 rear portion of interior illustration of 2 4 reporting measurement results 4 1 Quantum Design October 15 2003 Model 7100 AC Transport Controller connections to sample A 3 A 4 current provided by 3 2 5 4 5 7 5 10 dual measurement channels 3 2 3 6 4 9 electrical current operating modes comparison of 3 2 gain settings 3 3 3 4 in illustration of ACT electrical connections 2 6 A 1 installing 2 5 overview of operation 3 1 3 2 rear panel ports function of A 2 selecting current range for sample excitation 3 3 thermal cutoff limit adjusting 3 4 Output Range LEDs on Model 7100 3 3 P1 Sample Current Out port A 2 P2 Drive Access and Monitor port connections A 5 function 2 6 3 5 A 2 P3 Analog Interface port connections A 6 function A 2 P4 Digital Interface port connections A 6 function A 2 P5 Sample Signal In port connections A 3 function A 2 PPMS MultiVu software application automating ACT operation 1 1 4 1 5 3 See also ACT measurements Sequence mode installing 2 6 Preamp Gain LEDs on Model 7100 3 3 Raw measurement data files identifying selected See Data File tab storing raw voltage data 4 3 4 8 Raw voltage data saving when useful 4 3 Resistivity measurement description 1 2 1 3 5 5 harmonic detection in 1 3 in immediate mode 5 3 5 5 operating modes 4 1 5 3 parameters defining 5 5 sam
73. measurement results will be suspect WARNING A D converter over ranged on lowest gain EXPLANATION e Sample produced signal that exceeded capabilities of ACT to measure e No sample is connected to Model 7100 because puck is not plugged in or gray Lemo is not connected e Sample contacts are very poor POSSIBLE SOLUTIONS Excitation is too large Lower sample excitation Sample wiring has become disconnected Check the sample and instrument cabling Model 7100 internal connec tions are loose or disconnected Check internal ribbon cables No critical current detected for this measurement Sample did not produce desig nated voltage signal for the applied excitation at any time during measurement Sample wiring has become disconnected Check the sample and instrument cabling Sample not superconducting Adjust environmental and measurement parameters accordingly Quantum Design PPMS AC Transport Option User s Manual Rev D 1 October 15 2003 B 1 Section B 3 Error Messages B 3 B 2 Error Messages Appendix B Error and Warning Messages Error messages appear on a red background in the status bar that is at the bottom of the AC Transport control center Error messages indicate a serious hardware or software problem If a measurement is in progress when an error message appears the measurement results will be wrong If an error message appears you should investigat
74. metric current drive Select the gain setting used for voltage detection Always Autorange instructs the system to change the gain setting at the beginning of every measurement so that the optimum setting is selected Sticky Autorange prevents the system from changing gains until absolutely necessary Fixed Range restricts the system to the use of a single user specified gain setting Select the sample Sample 1 or Sample 2 you want to measure PPMS AC Transport Option User s Manual Rev D 1 5 7 October 15 2003 Section 5 3 Chapter 5 ACT Measurements Measurements 5 3 2 4 RUN THE MEASUREMENT 1 Select the Measure button The measurement begins The Measure button now reads Cancel You select Cancel to abort the measurement To measure the Hall coefficient the designated alternating current is driven through the appro priate channel for the specified duration The Model 7100 preamp board amplifies the detected Hall voltage before it is sampled by the digital signal processor on the AC board and analyzed by the software The Hall coefficient is calculated with equation 1 3 The Status panel at the bottom of the AC Transport control center indicates the status of the on going measurement The system temperature magnetic field and sample position are measured at the beginning and end of the resistivity measurement and their average values are reported As soon as the measurement is complete the Waveform tab in the control center opens
75. ms you want to save to the measurement data file By default the general system status system temperature magnetic field sample position and the reading from mappable channel 23 user thermometer are saved to the data file The appearance of the PPMS Data tab in all the ACT sequence measurement dialog boxes is identical Figure 5 8 illustrates the PPMS Data tab in the Resistivity dialog box Select OK The Critical Current command is added to the sequence Select the Save Sequence File button in the PPMS MultiVu tool bar Re name the sequence if you like 5 3 8 2 PREPARE FOR THE MEASUREMENT 1 Mount the sample on a sample puck and connect the sample leads so that you can perform a four wire resistivity measurement Refer to section 5 2 Insert the sample into the sample chamber Select the Install tab in the AC Transport control center and then follow the software prompts Select the Data File tab in the AC Transport control center The tab indicates which data files are selected to save the measurement data Click on Browse to select a different file or create a new file see section 4 4 1 If a data file is selected sequence measurement data is automatically saved to that file If no data file is selected the sequence will not start 5 3 8 3 RUN THE SEQUENCE 1 Ouantum Design Select the Run Sequence button in the PPMS MultiVu tool bar You have saved your new sequence so it should run immediately Wait for the se
76. n the PPMS MultiVu tool bar You have saved your new sequence so it should run immediately Wait for the sequence run to finish While the sequence runs status messages in the sequence control center and the sequence status panels indicate that a sequence is running The commands in the sequence determine the length of time the sequence runs When the run is complete all Run commands are enabled and the sequence control center and the sequence status panels both indicate the sequence status is Idle The sequence measurement data is automatically saved to the data file you selected in section 5 3 7 2 PPMS AC Transport Option User s Manual Rev D 1 5 17 October 15 2003 Section 5 3 ACT Measurements Chapter 5 Measurements 5 3 8 Taking Critical Current Measurements in Seguence Mode Caution The ACT critical current measurement automatically adjusts the critical voltage for voltage offsets seen at the beginning of each measurement For this reason it is important to use the critical current feature with only superconducting samples amp For detailed information about creating and editing sequence files oO and for a discussion about all standard PPMS sequence commands NOTE Application User s Manual refer to the Physical Property Measurement System PPMS MultiVu 5 3 8 1 CREATE THE SEQUENCE COMMAND Select a new or existing sequence file 2 Select the Critical Current measurement command which is in the Measureme
77. nals or when operating at frequencies commensurate with the power line It is recommended that these noisier frequencies be avoided during sensitive AC measurements Quantum Design PPMS AC Transport Option User s Manual Rev D 1 1 5 October 15 2003 Section 1 3 Chapter 1 ACT Measurement Types Theory of Operation 1 3 3 I V Curve Measurements The ACT option performs current versus voltage traces for any sample or device wired to the Model 7100 AC Transport Controller Physical connections to the sample are made just as they are made for resistivity measurements see section 1 3 1 The DC current through the sample is ramped up or down in small discrete steps up to 256 steps per quadrant are allowed The current may start at zero and ramp up to a specified maximum positive or negative current or it may start at the specified maximum current and ramp down to zero As the current changes the voltage drop across the sample is measured and recorded Measurements are digital so a continuous trace is not actually performed A discrete number of current and voltage readings is taken throughout the current ramp pattern and a plot of V versus I is then generated Figure 1 5 The current through the sample during l V traces can be ramped up to or down from a specified maximum current An l V trace may contain any portion of the ramp sequence shown to the left providing that it begins and ends at I max max or zero CURRENT I
78. ne 4 4 Figure 4 4 Waveform Tab in AC Transport Control Center eese eene nennen 4 5 Figure 4 5 Configure Tab in AC Transport Control Center eese enne enne nennen 4 6 Fig re 4 6 ACT Status E08 uote p m ter oe ine tate rie Le aden E e eie are dei tede idest 4 7 Figure 5 1 Wiring Examples for ACT Measurements essere enne trennt tnen netten 5 1 Figure 5 2 Dialog Box for Defining Resistivity Measurement in Immediate Mode sees 5 4 Figure 5 3 Balance Meter Dialog BOX iaiuceegp erem DEREN CHER e SE Le ER RERO e niens 5 6 Figure 5 4 Dialog Box for Defining Hall Coefficient Measurement in Immediate Mode 5 7 Figure 5 5 Dialog Box for Defining I V Curve Measurement in Immediate Mode sess 5 9 Figure 5 6 Dialog Box for Defining Critical Current Measurement in Immediate Mode 5 11 Figure 5 7 Sample 1 Tab in Dialog Box for Defining Resistivity Measurement in Sequence Mode 5 13 Figure 5 8 PPMS Data Tab in Dialog Box for Defining Resistivity Measurement in Sequence Mode 5 13 Figure 5 9 Sample 1 Tab in Dialog Box for Defining Hall Coefficient Measurement in Sequence Mode 5 15 Figure 5 10 Sample 1 Tab in Dialog Box for Defining I V Curve Measurement in Sequence Mode 5 17 Figure 5 11 Sample 1 Tab in Dialog Box for Defining Criti
79. nt Commands group in the sequence command bar and define the command as follows e Select the Sample 1 tab in the Critical Current dialog box figure 5 11 to set the measurement parameters for a sample wired to channel 1 on the Model 7100 Verify that the Measure check box is selected so that the sample is measured Then set the parameters as necessary Refer to section 5 3 4 2 to review how to set the parameters e Select the Sample 2 tab in the Critical Current dialog box to set the measurement parameters for a sample wired to channel 2 on the Model 7100 Verify that the Measure check box is selected so that the sample is measured Then set the parameters as necessary Refer to section 5 3 4 2 to review how to set the parameters Notice that one sequence measurement can measure two samples The system measures sample 1 then it measures sample 2 ACT Critical Current Eg Sample 1 Sample 2 PPMS Data Max Current pn m DmicdVokege int Power Limit Bi mw HecoxTme E Averaging Time ine rl Measures Ri Ranging V Limited ow ig 40uv C Fixed cen us Figure 5 11 Sample 1 Tab in Dialog Box for Defining Critical Current Measurement in Seguence Mode 5 18 PPMS AC Transport Option User s Manual Rev D 1 Ouantum Design October 15 2003 Chapter 5 Measurements Section 5 3 ACT Measurements e Select the PPMS Data tab in the Critical Current dialog box and then select the data ite
80. nt panel of the Model 7100 AC Transport Controller to select a voltage that is between the two positive voltage leads Complete the following steps 1 2 3 4 Set the magnetic field to zero and wait for the system to stabilize at zero field Select Measure Balance Meter The Balance Meter dialog box opens figure 5 3 Select the sample you will measure Select the resolution if necessary In most cases the Auto resolution is sufficient E ACT Balance Meter p x r Balance Divetuc Sample 1 imi r Resolution C Low x1 Auto P 10004 C High x100 C Other mA 1 Ohm 1 Ohm 1 u0hm ON UNE LBE ABA AAI BBA BAA NBA BE BEL Start E Help Figure 5 3 Balance Meter Dialog Box Select a drive current You should specify the largest possible drive current that will not rail the electronics or destroy the sample A large drive current produces a large signal so it is easier to zero the signal Instead of selecting a very large drive current you can alternatively select the drive current that is closest to the measurement current Select Start Turn the Balance potentiometer for the appropriate channel until the offset is as close to zero as possible The Balance pots are on the front panel of the Model 7100 Watch the display area at the bottom of the Balance Meter dialog box Notice that there is a delay between when you adjust the pot and when
81. onnector on the cable labeled PS Sample Voltage In into the P5 Sample Voltage In port on the rear of the Model 7100 e Plug the 4 pin Lemo connector on the cable labeled P2 System Bridge into the small round port next to the P2 System Bridge port on the rear of the Model 6000 PPMS AC Transport Option User s Manual Rev D 1 Ouantum Design October 15 2003 Chapter 7 Section 7 3 Operation with the Horizontal Rotator Rotator Thermometer Configuration Caution 7 3 1 he PPMS now uses the rotator thermometer to control the temperature and the rotator motor is configured properly Data files written by the ACT software now report the rotator thermometer reading in K under the item labeled PPMS Map 20 For ACT options shipped prior to March 1997 a simple modification to the HRACT cfg file is required to allow the ACT software to report the rotator temperature Quantum Design Customer Service can help you with this file modification If you connect the standard ACT Y connection cable to the probe head while the Horizontal Rotator probe is installed you are essentially connecting a high power current source to a calibrated negative temperature coefficient resistive thermometer with resistance between 20 10 000 O Depending on its temperature this thermometer can be damaged by as little as 10 uA to 10 mA so you should not use the standard cable when the Horizontal Rotator probe is installed in
82. or select Back to open the Sample 1 tab PPMS AC Transport Option User s Manual Rev D 1 4 9 October 15 2003 Section 4 4 Chapter 4 ACT Data Files Software g Select Finish in the Sample 2 tab when you have finished defining sample property information and are ready to create the data file The Data File tab appears again and displays the name of the data file you have created The data entry fields in the Sample tabs are disabled You cannot change any of the information written to the data file header 8 Enable the Capture Raw Data check box if you want to save the raw voltage data to a raw measurement data file Saving raw voltage data can be useful but requires a significant amount of disk space The raw measurement data file will have the identical base name as the measure ment data file Once you select a data file or data files all subsequent measurement data is saved to those files until you use the ACT software to either select new files or no file 4 10 PPMS AC Transport Option User s Manual Rev D 1 Quantum Design October 15 2003 C H APTER 5 Measurements 5 1 5 2 Introduction This chapter contains the following information e Section 5 2 discusses how to mount e Section 5 3 explains how to take ACT samples on sample pucks measurements in immediate mode and sequence mode Sample Mounting Procedures The ACT option can be used in conjunction with ACT or PPMS sample pucks or with the PPMS Horizontal Rota
83. ort current measurements including measurements that require ramping a DC current Measurements are typically made by passing a known current through the sample and measuring the voltage drop across the sample in one direction The ACT option can be used with samples mounted on sample pucks or sample rotators The ACT option can supply an AC bias current from 1 Hz up to 1 kHz and can therefore provide greater measurement sensitivity than DC instruments because signal filtering can be employed The quantity of interest is generally a component with a form similar to the driving form and a known frequency so all other components of the sample signal can be subtracted off eliminating frequency dependent noise DC offset and instrumental drift In the ACT option digital filtering precisely isolates the sample signal The ACT software module is integrated into the PPMS MultiVu software application which controls and monitors the PPMS hardware While you work with the ACT option you may use any PPMS MultiVu commands PPMS MultiVu and ACT software commands can fully automate system operation so you can run a wide range of measurements without being present in the laboratory The Physical Property Measurement System PPMS MultiVu Application User s Manual discusses PPMS MultiVu in detail Quantum Design PPMS AC Transport Option User s Manual Rev D 1 1 1 October 15 2003 Section 1 3 Chapter 1 ACT Measurement Types Theory of Operation 1 3
84. ou want to measure Select the gain ranging mode V Limited voltage limited mode instructs the system to calcu late a gain based on the specified Voltage Limit Fixed mode restricts the system to the use of a single user specified gain setting PPMS AC Transport Option User s Manual Rev D 1 5 11 October 15 2003 Section 5 3 Chapter 5 ACT Measurements Measurements 5 3 4 3 RUN THE MEASUREMENT 1 Select the Measure button The measurement begins The Measure button now reads Cancel You select Cancel to abort the measurement To measure critical current a DC current on the designated channel is stepped up towards the maximum test current in discrete steps and at each step the voltage drop is monitored and averaged When the critical voltage specified in the Voltage Limit text box is measured the ramp is stopped and the current is recorded as the critical current The current is shut off and the sample is allowed to cool for the specified re cool time This process is then repeated and the average critical current for the number of trials performed is reported If the maximum current or the power limit is reached before the critical voltage is measured the measurement is aborted and an error condition is reported The Status panel at the bottom of the AC Transport control center indicates the status of the on going measurement As soon as the measurement is complete the Waveform tab in the control center opens and displays a diagnos
85. ple property information affecting 1 2 4 8 4 9 saving data from 5 3 5 5 5 12 in sequence mode 5 12 5 14 wiring sample for on ACT sample puck 1 2 1 3 5 1 5 2 See also Sample wiring Standard PPMS sample puck Resistivity option using with ACT option A 3 using with Horizontal Rotator option 7 2 Rotator thermometer connecting to system bridge board 7 2 7 3 Quantum Design PPMS AC Transport Option User s Manual Rev D 1 Index Sample chamber identifying status of 4 2 Sample connections for ACT system A 3 A 4 Sample mounting See Sample wiring Sample tabs in AC Transport control center 4 3 4 4 Sample wiring See also Sample connections on ACT sample puck for Hall measurement 1 4 1 5 5 1 5 2 for resistivity measurement 1 2 1 3 5 1 5 2 on Helium 3 sample mount 6 3 on Horizontal Rotator platform 7 4 on standard PPMS sample puck 3 6 5 2 Sequence mode measurements in See ACT measurements Sequence mode Sticky autorange gain setting definition of 3 3 System status identifying in AC Transport control center 4 2 in ACT status log 4 7 Thermal Cutoff Adjustment potentiometer adjusting 3 4 UserTemp turning off 7 3 Voltage lead separation of sample defining 4 4 4 8 4 9 Voltage Limited LED when lit 3 3 3 4 Warning messages listed B 1 recorded in ACT status log 4 7 shown in AC Transport control center 4 2 B 1 Waveform tab in AC Transport control center 4 5 Index 3 Octobe
86. pter 3 Hardware 3 3 3 4 Section 3 4 Cables and Jumpers Model 6000 AC Board The AC board is installed in the Model 6000 PPMS Controller and is located behind the P3 Option port which is the port connecting the Model 6000 to the Model 7100 The AC board includes a DSP digital to analog converter DAC current drivers and other control electronics that are necessary to synthesize excitation signals and process sample response signals The DSP provides the excitation waveform and processes the sample signal The AC board is essentially the same board used with the AC Measurement System ACMS option but with an addition to the ROMs The AC board is specially calibrated for use with each set of ACT or ACMS hardware Cables and Jumpers The ACT option includes one 9 pin cable one 15 pin cable and one Y cable The unique Y cable connects the sample to the Model 7100 and is specifically designed for the extremely sensitive ACT option The Y cable arrangement splits the sample signal and excitation signal into two separate shielded cables designed to help prevent sample signal distortion by the excitation signal T PL SAMPLE E CURRENT DUT a DE cat P5 SAMPLE VOLTAGE IN Figure 3 3 ACT Y Connection Cable The PPMS Horizontal Rotator option and
87. pts 3 Select the Data File tab in the AC Transport control center The tab indicates which data files are selected to save the measurement data Click on Browse to select a different file or create a new file see section 4 4 1 If a data file is selected sequence measurement data is automatically saved to that file If no data file is selected the sequence will not start Quantum Design PPMS AC Transport Option User s Manual Rev D 1 5 13 October 15 2003 Section 5 3 Chapter 5 ACT Measurements Measurements 5 3 5 3 RUN THE SEQUENCE 1 Select the Run Sequence button in the PPMS MultiVu tool bar You have saved your new sequence so it should run immediately 2 Wait for the sequence run to finish While the sequence runs status messages in the sequence control center and the sequence status panels indicate that a sequence is running The commands in the sequence determine the length of time the sequence runs When the run is complete all Run commands are enabled and the sequence control center and the sequence status panels both indicate the sequence status is Idle The sequence measurement data is automatically saved to the data file you selected in section 5 3 5 2 5 3 6 Taking Five Wire Hall Measurements in Sequence Mode a Ee For detailed information about creating and editing sequence files Cj and for a discussion about all standard PPMS sequence commands NOTE refer to the Physical Property Measurement System PPMS Mul
88. quence run to finish While the sequence runs status messages in the sequence control center and the sequence status panels indicate that a sequence is running The commands in the sequence determine the length of time the sequence runs When the run is complete all Run commands are enabled and the sequence control center and the sequence status panels both indicate the sequence status is Idle The sequence measurement data is automatically saved to the data file you selected in section 5 3 8 2 PPMS AC Transport Option User s Manual Rev D 1 5 19 October 15 2003 C H APTER 6 Operation with the Helium 3 System 6 1 Introduction This chapter contains the following information e Section 6 2 presents an overview of ACT e Section 6 4 contains interconnection operation with the Helium 3 system tables for the ACT Helium 3 probe cable e Section 6 3 describes how to take ACT measurements when using the Helium 3 system 6 2 Overview of ACT Operation with the Helium 3 System The ACT option may be used with the PPMS Helium 3 Refrigerator System insert Model P825 Use of the Helium 3 insert allows ACT measurements to be performed to below 0 4 K The Helium 3 system is designed to be as transparent as possible so that ACT operations are performed normally when the Helium 3 insert is in use The internal wiring in the Helium 3 insert cannot handle sample currents larger than approximately 20 mA Consequently under normal opera
89. r 15 2003
90. rallel to those ends see figure 1 2 This arrangement of the current leads passes a more uniform current through bar shaped samples You may use a rectangular lead arrangement to measure anisotropic samples You are responsible for determining the best lead arrangement for your needs and for interpreting the resulting data 1 2 PPMS AC Transport Option User s Manual Rev D 1 Quantum Design October 15 2003 Chapter 1 Section 1 3 Theory of Operation ACT Measurement Types CDNDUCTIVE PADS ON ENDS DF BAR N N N N N N N hy I Vt y ie Figure 1 2 Common Lead Arrangement for Bar Shaped Samples 1 3 1 1 HARMONIC DETECTION During resistivity measurements the detected second and third harmonics of the response signal voltage are reported in dB referenced to the fundamental response signal voltage This information can be related to nonlinearities in the sample but it frequently indicates the amount of noise encountered during the measurement The second and third harmonic contribution is usually less than 50 dB for a clean measurement and is larger when looking at very small signals or when operating at frequencies commensurate with the power line It is recommended that these noisier frequencies be avoided during sensitive AC measurements 1 3 2 Hall Coefficient Measurements The ACT option supports four wire and five wire Hall coefficient measurements The ACT option can also be used to examine how the Hall voltage vari
91. rd ACT sample puck ACT Y connection cable Model 7100 AC Transport Controller installation kit components in 2 1 installing 2 2 2 6 measurement types 1 1 1 2 4 1 See also Critical current measurement Hall coefficient measurement I V curve measurement Resistivity measurement operating with other options See Helium 3 Refrigerator System option Horizontal Rotator option pinout tables A 3 A 5 A 6 providing increased measurement sensitivity 1 1 sample holders compatible with 1 1 3 6 5 1 software files 4 1 Quantum Design PPMS AC Transport Option User s Manual Rev D 1 AC Transport control center commands executing immediately 5 3 function 4 2 5 3 opening 2 6 4 2 tabs in 4 2 4 6 ACT sample puck connecting solder pads for negative voltage leads 1 5 3 6 dual channels on 3 6 5 1 5 3 5 12 samples correctly wired to illustration of 5 1 wiring sample to for Hall measurement 1 4 1 5 5 1 5 2 for resistivity measurement 1 2 1 3 5 1 5 2 ACT software See also AC Transport control center activating in PPMS MultiVu 2 6 creating data files See Measurement data files Raw measurement data files installing 2 6 integrated into PPMS MultiVu 1 1 2 6 4 1 measuring power line frequency on start up 1 6 ACT status log 4 6 4 7 ACT Y connection cable in illustration of ACT electrical connections 2 6 A 1 splitting sample and excitation signals 3 5 Always autorange gain setting definition of 3 3 Aniso
92. rement data is saved only if a measurement data file is selected Raw voltage data is saved only if a sample measurement data file is selected and the Capture Raw Data check box is enabled You may run measurements when a data file is not selected but the measurement data is discarded Install Data File Sample 1 Sample 2 Waveform Configure Path File Name NewAETFleEBda CSCS aa IV Capture Raw Data Browse View IV Curve Critical Curent Hall Coefficient Status Measure complete Good Gain at 5000m Range Figure 4 2 Data File Tab in AC Transport Control Center You can use the Data File tab to select or create a data file The Browse button in the tab opens the AC Transport Select Data File dialog box which lists all existing files and lets you create a new measurement data file When you create a new file the software prompts you to define the sample properties for the sample or samples whose measurement data will be saved to the file and the data entry fields in the Sample 1 and Sample 2 tabs are enabled Because the sample information is stored in the data file header it must be specified when the data file is created and cannot be changed later Saving raw voltage data is an option The raw data is saved to a separate raw measurement data file that has the identical base name as the measurement data file but a raw file extension instead of a dat extension Saving the raw voltage data can be useful
93. rement in Sequence Mode 3 4 e Select the PPMS Data tab in the IV Curve dialog box and then select the data items you want to save to the measurement data file By default the general system status system temperature magnetic field sample position and the reading from mappable channel 23 user thermometer are saved to the data file The appearance of the PPMS Data tab in all the ACT sequence measurement dialog boxes is identical Figure 5 8 illustrates the PPMS Data tab in the Resistivity dialog box Select OK The IV Curve command is added to the sequence Select the Save Sequence File button in the PPMS MultiVu tool bar Re name the sequence if you like 5 3 7 2 PREPARE FOR THE MEASUREMENT 1 Mount the sample on a sample puck and connect the sample leads so that you can perform a four wire resistivity measurement Refer to section 5 2 Insert the sample into the sample chamber Select the Install tab in the AC Transport control center and then follow the software prompts Select the Data File tab in the AC Transport control center The tab indicates which data files are selected to save the measurement data Click on Browse to select a different file or create a new file see section 4 4 1 H a data file is selected sequence measurement data is automatically saved to that file If no data file is selected the sequence will not start 5 3 7 3 RUN THE SEQUENCE 1 Quantum Design Select the Run Sequence button i
94. rements A special four way probe cable see figure 7 1 splits off the four thermometer wires that go to the system bridge board from the dedicated ACT wiring that goes to the Model 7100 AC Transport Controller Refer to the Physical Property Measurement System Horizontal Rotator Option User s Manual for more information about using the Horizontal Rotator Quantum Design PPMS AC Transport Option User s Manual Rev D 1 7 1 October 15 2003 Section 7 3 Chapter 7 Rotator Thermometer Configuration Operation with the Horizontal Rotator 7 3 7 2 Rotator Thermometer Configuration The rotator thermometer can be used only if it is plugged into the user bridge board or the system bridge board in the Model 6000 PPMS Controller The four way cable part number 3084 517 shipped with the Horizontal Rotator ACT kit allows the rotator thermometer signals to be directed to the bridge board while sample signals are directed to the Model 7100 C E HEHBHH Figure 7 1 ACT Horizontal Rotator Probe Cable When the system is using the ACT Horizontal Rotator probe cable the rotator thermometer should be connected to the system bridge board You complete the following steps to configure the PPMS and use the rotator thermometer 1 Vent the PPMS sample chamber and install the rotator support plate Then insert the rotator probe into the sample chamber Insert the disk included with the Horizontal Rotator option
95. rovides as much as 2 A of current This large current can damage samples and other equipment in the current path Use only currents that can be safely handled by all hardware and samples in the circuit Use the Frequency text box to specify a frequency in hertz for the sample excitation signal Avoid integer multiples of the power line frequency Use the Duration text box to specify the time in seconds over which the ACT will measure the voltage across the sample Verify that the Constant Current Mode check box is enabled if you want the Model 7100 to operate in constant current mode Disable the check box only to make the Model 7100 operate in low impedance mode In constant current mode the Model 7100 adjusts the potential drop across the current leads in order to maintain a desired current through the sample regardless of sample resistance see section 3 2 1 Enable the Low Resistance Mode check box only if the sample has a resistance less than approximately 1 uQ and you want to reduce the compliance voltage at the current driver by a factor of 10 in order to provide a more symmetric current drive PPMS AC Transport Option User s Manual Rev D 1 Quantum Design October 15 2003 Chapter 5 Measurements 5 3 2 Ouantum Design Section 5 3 ACT Measurements Select the gain setting used for voltage detection Always Autorange instructs the system to change the gain setting at the beginning of every measurement so that the optimum s
96. s The Measure button now reads Cancel You select Cancel to abort the measurement The Status panel at the bottom of the AC Transport control center indicates the status of the on going measurement and summarizes the results when the measurement is complete The Waveform tab in the control center opens as soon as the measurement is complete and displays a diagnostic plot of the measurement The I V Curve dialog box displays the average tempera ture magnetic field and sample position used during the last I V trace The result of one I V trace is an entire set of data Unlike most measurements with the PPMS the time stamp accompanying each data point is not the exact time of the measurement but is an approximation of the measurement time according to the measurement parameters Examine the diagnostic plot of the measurement in the Waveform tab This plot shows you the results of the I V curve trace Select the Save button if you want to save the results of the measurement to the specified data file or files You must select Save in order to save the data Taking Critical Current Measurements in Immediate Mode The ACT critical current measurement automatically adjusts the critical voltage for voltage offsets seen at the beginning of each measurement For this reason it is important to use the critical current feature with only superconducting samples 5 3 4 1 PREPARE FOR THE MEASUREMENT 1 Mount the sample on a sample puck and conn
97. s Manual Rev D 1 2 1 October 15 2003 Section 2 3 Chapter 2 Installation Procedures Installation 2 3 2 3 1 Caution Caution 2 2 Installation Procedures ACT option installation consists of the following procedures 1 installing the AC board in the Model 6000 PPMS Controller 2 installing the Model 7100 AC Transport Controller in the PPMS electronics cabinet 3 attaching the electrical cables and 4 installing the software on the host computer You need the following tools to install the ACT option M Phillips head screwdriver M 3 16 in socket driver or needle nose pliers or pair of blunt tweezers Install the AC Board The AC board used with the ACT option is essentially the same board used with the PPMS AC Measurement System ACMS option However even if the ACMS option is already installed on your system you must install the new AC board because each board is calibrated to work with the individual ACMS or ACT hardware Static discharge can damage components in the Model 6000 Before you touch the AC board or any other component inside the Model 6000 ground yourself by touching the metal back or metal side panel of the Model 6000 case In addition limit your movement during installation and whenever you handle the AC board movement increases the possibility of static discharge Complete the following steps to install the AC board Set the system magnetic field to zero in persistent mode and
98. se 1 3 Figure 1 3 Four Wire Hall Effect Measurement for Sample with Negative Charge Carriers 1 4 Figure 1 4 Leads Attached for Four Wire and Five Wire Hall Coefficient Measurements esee 1 5 Figure 1 5 Current through Sample during I V Traces Can Be Ramped Up or Down eee 1 6 Figure 1 6 Example EV CUVE oie ret ehe ett e eee ep icri d tei etude pi cher ea 1 6 Figure 2 1 Remove the Top Cover of the Model 6000 sessi enne nennen nennen enne 2 3 Figure 2 2 Top View of Rear Portion of Model 6000 Interior eese enne 2 4 Figure 2 3 Removing the Blank Panel 5 5 3 nicer ep ni Ro erbe bati deterior Pete rb Teas 2 5 Eigure 2 4 AGT Connections eect d rere cc BORDER partage tip eid Oed 2 6 Figure 3 1 Front Panel on Model 7100 AC Transport Controller essere enne 3 1 Figure 3 2 Available Current As a Function of Voltage Drop Across the Current Leads sss 3 2 Figure 3 3 ACT Y Connection Cable 5 teen gie tite egere dap rete ted deeper oes 3 5 Figure 3 4 ACT Sample Puck reia tea RU p e EU Ur a UR REEL Te een 3 6 Figure 4 1 Install Tab in AC Transport Control Center eese enne enne 4 2 Figure 4 2 Data File Tab in AC Transport Control Center esee ener eene 4 3 Figure 4 3 Sample Tabs in AC Transport Control Center eese enne en
99. signal and sends the signal back to the DSP so the DSP can process the signal The sample signal can be very small so the preamp board is enclosed in a metal casing to shield the signal from magnetic fields The ten turn potentiometers on the Model 7100 are also enclosed in a metal casing The Model 7100 can measure samples on channel or on channel 2 The channel used for a measurement is set when the measurement is defined The Measure LEDs on the front panel of the Model 7100 figure 3 1 indicate which channel is being used The ten turn Balance potentiometers null the offset between negative and positive voltage leads prior to five wire Hall coefficient measurements Two BNC outputs on the Model 7100 front panel let another instrument such as an oscilloscope be used to monitor the current passed through the sample and the voltage drop across the sample The BNC outputs attenuate signals by 20 dB decade above approximately 14 kHz This is a property of the outputs and not of the drive electronics The full scale of the current monitor BNC is 2 V i e a reading of 2 V in the 200 mA range means that 200mA is being sent out while the voltage monitor BNC reading must be divided by the preamp gain to obtain the readback voltage The Model 7100 provides as much as 2 A of current This large current can damage samples and other equipment in the current path Use only currents that can be safely handled by all hardware and sampl
100. software options Bold text and all capital letters distinguish the names of keys located on the front panel of the Model 6000 PPMS Controller The Courier font distinguishes characters you enter from the PC keyboard or from the Model 6000 PPMS Controller front panel The Courier font also distinguishes code and the names of files and directories Angle brackets distinguish the names of keys located on the PC keyboard A plus sign connecting the names of two or more keys distinguishes keys you press simultaneously A pointing hand introduces a supplementary note Introduces a cautionary note Introduces a warning PPMS AC Transport Option User s Manual Rev D 1 October 15 2003 Quantum Design C H A P T E R I1 Theory of Operation 1 1 1 2 Introduction This chapter contains the following information e Section 1 2 presents an overview of the e Section 1 3 explains the theory of each AC Transport Measurement System AC Transport measurement type Overview of the ACT Option The Quantum Design AC Transport Measurement System ACT option incorporates a precision current source and a precision voltmeter in a package configured for use with the base Physical Property Measurement System PPMS platform The precision current source has a resolution of 0 02 uA and a maximum current of 2 A The precision voltage detector has a similarly sized range The ACT option can thus support several different types of electrical transp
101. stalled 6 2 6 4 using ACT Helium 3 probe cable 6 1 6 2 Helium 3 sample mount wiring sample to 6 3 High impedance mode See Constant current mode Horizontal Rotator option configuring rotator thermometer for 7 2 7 3 taking ACT measurements when installed 7 1 7 4 using ACT Horizontal Rotator probe cable 7 1 7 2 7 3 HR cfg file 7 2 HRACT cfg file 7 2 7 3 Immediate mode measurements in See ACT measurements Immediate mode Installation See ACT option Installing Install tab in AC Transport control center 4 2 4 8 I V curve measurement current versus voltage trace 1 6 in immediate mode 5 8 5 10 operating modes 4 1 5 3 parameters defining 5 8 5 10 saving data from 5 3 5 8 5 10 5 17 5 19 in sequence mode 5 16 5 18 time stamp as approximate measurement time 5 9 as variant of resistivity measurement 1 2 wiring sample for See Resistivity measurement Wiring sample Line averaging time 5 11 Low impedance mode comparison with constant current mode 3 2 disabling I V curve power limit 5 8 drive source impedance determining 3 3 when useful 3 2 Masonite blank panel installing 2 5 Measure LEDs on Model 7100 3 2 Measurement data files creating 4 0 4 10 header in information written to 4 3 4 4 4 8 4 0 identifying selected See Data File tab storing sample measurement data 4 3 4 8 storing system data items 4 8 5 4 5 12 Model 6000 PPMS Controller housing AC board 3 1 3 5 See a
102. supply the two other parameters that are necessary to calculate the resistivity 1 the voltage lead sep aration and 2 the cross sectional area through which the current passes A The ACT software reports resistivity or linear resistance in units you can configure Note the geometric configuration of the leads in figure 1 1 The current leads create a field within bar shaped or bulk samples so the voltage leads should be arranged such that they measure a potential drop across a region where the field lines are relatively straight that is in line with the current leads or separated by a distance that is small compared to their distance from the current leads Otherwise the resistivity measurements tend to be misleading In figure 1 1 you should also note that the current and voltage leads do not contact the sample at the same point If the current and voltage leads contact the sample at the same point lead resistance is eliminated but contact resistance still affects the mea surement It is important to perform true four wire measurements with the ACT option in order to take advantage of the instrument s sensitivity You may use other geometric configurations of the leads during certain types of four terminal resistivity measurements For example when you measure bar shaped samples you may attach the current leads to conductive pads that contact the entire end of the sample and then make the voltage leads contact the sample in a line pa
103. surements Caution 5 4 Chapter 5 Measurements Select the Data File tab in the AC Transport control center The tab indicates which data files are selected to save the measurement data Click on Browse to select a different file or create a new file see section 4 4 1 If you run the measurement when no data file is selected the data is discarded 5 3 1 2 DEFINE THE MEASUREMENT 1 Select the Resistivity button in the AC Transport control center The Resistivity dialog box for an immediate mode measurement opens Items in the upper part of the dialog box designate measurement conditions that should be set prior to selecting the Measure button Items in the lower part of the dialog box display the results of the last resistivity measurement ACT Resistivity i x Excitation Last Measure 7 Amplitude ho m Temp o K Frequency 30 Hz Field ro000 De Duration E Sec Position 30 deg Ee S Always Autorange IV Constant Current Mode Sticky Autorange LowResistance Mode FixedRange Tr Resistivity Sample 1 C Sample 2 Uem ET TYT he a Haw ME DS Ben ac Figure 5 2 Dialog Box for Defining Resistivity Measurement in Immediate Mode Use the Amplitude text box to specify a small current in milliamperes that will not harm the sample The current is the amplitude of the sine wave excitation applied to the sample The Model 7100 p
104. t on Model 6000 P5 Sample Signal In 8 pin Lemo connector marks location where voltage signal from sample is directed into Model 7100 Opposite ends of Y cable making this connection attach to P1 port on Model 7100 and to gray Lemo connector on probe head A 2 PPMS AC Transport Option User s Manual Rev D 1 Quantum Design October 15 2003 Appendix A Section A 4 Connections Ports and Pinouts Pinout Tables A 4 Pinout Tables The following tables detail the pinouts for each connector in the ACT system All diagrams accompanying the tables illustrate hardware ports not connectors at the end of the cables A 4 1 Sample Connections Connections from the Model 7100 to the sample are configured to minimize cross talk between the excitation signal and the detected signal For this reason Model 7100 sample connections are different from sample connections to the Model 6000 user bridge board Solder pads on sample pucks and sample rotators contact different pins when they are connected to the Model 7100 and when they are connected to the user bridge board If you want to use both the Model P400 Resistivity option user bridge board and the ACT option to measure the same sample and you do not want to rewire the connections on the puck or rotator you may find it useful to create an adapter that translates bridge board pinouts to Model 7100 pinouts Table A 2 charts the connections to the sample puck from the Model 7100 Fig
105. talled the current output is ma ee limited to 20 mA or less 2A 10Q Gain Settings The gain setting mode is selected when a resistivity Hall coefficient or I V curve measurement is defined Three gain setting modes are available always autorange sticky autorange and fixed range In always autorange mode the system in order to pick the optimum gain setting changes the gain at the beginning of every measurement The highest gain setting that does not rail the A D converter is selected In contrast in sticky autorange mode the system delays changing gain until the signal is off scale and the signal is off scale when it is greater than the maximum voltage for that setting or when it is less than 20 of the maximum voltage for that setting as shown in table 3 2 Consequently the gain is changed less frequently in sticky autorange mode Fixed range mode locks the system into a single user specified gain setting so an incorrect gain setting can be selected resulting in less than optimal sensitivity or data loss due to A D converter saturation The Preamp Gain LEDs on the Model 7100 front panel indicate the preamp gain setting One Preamp Gain LED should always be lit while the Model 7100 power is on The AC board in the Model 6000 PPMS Controller also applies a gain to the signal This gain is not indicated on the front of the hardware PPMS AC Transport Option User s Manual Rev D 1 3 3 October 15 2003 Section 3 2
106. the PPMS Helium 3 Refrigerator System option require special four way cables to simultaneously interface with the ACT option and the Model 6000 temperature control hardware These special cables which replace the Y cable normally used with the ACT option allow the rotator thermometer to be connected to the system bridge board or to the user bridge board in the Model 6000 A dongle that connects to the P2 Drive Access and Monitor port on the rear panel of the Model 7100 is also included It contains jumpers to complete the drive circuitry of the Model 7100 and should only be removed from the Model 7100 when access to the drive breakout is required Quantum Design PPMS AC Transport Option User s Manual Rev D 1 3 5 October 15 2003 Section 3 5 Chapter 3 ACT Sample Pucks Hardware 35 ACT Sample Pucks The surface of each ACT sample puck has a mounting circuit board with labeled contact pads for convenient sample wiring on two separate channels that are read by the Model 7100 The soft gold plated contact pads on the ACT sample pucks allow either wire bonding or soldering ACT sample pucks automatically connect the two solder pads for the two negative voltage leads used during five wire Hall coefficient measurements H c A Top View B Side View
107. the sample chamber To avoid damaging the rotator thermometer when the Horizontal Rotator probe is installed in the sample chamber use only the ACT Horizontal Rotator probe cable and never use the standard ACT Y connection cable Turning Off UserTemp Configuring the Horizontal Rotator by transmitting the configuration files to the Model 6000 ROM also turns on UserTemp so that the rotator thermometer is used for temperature control When you complete your experiments with the Horizontal Rotator and remove the Horizontal Rotator probe from the sample chamber you should turn off this thermometer Complete the following steps 1 Open Monitor QD 6000 in the PPMS 32 bit Tools folder or select Utilities Send GPIB Commands in the PPMS MultiVu interface 2 TypeUSERTEMP 0 3 Press Enter to execute this command If you do not turn off UserTemp the resistance read off system bridge channel 4 is used to control the temperature in the sample chamber If UserTemp remains on but no user thermometer is installed that is the Horizontal Rotator probe is removed from the PPMS the temperature control defaults back to the system thermometers but returns to system bridge channel 4 whenever a resistance is perceived there If the resistance is not that of the calibrated rotator thermometer the temperature controller appears broken so be sure to turn off UserTemp when you are not using the Horizontal Rotator or another custom
108. tiVu Application User s Manual 5 3 6 1 CREATE THE SEQUENCE COMMAND Select a new or existing sequence file 2 Select the Hall Coefficient measurement command which is in the Measurement Commands group in the sequence command bar and define the command as follows e Select the Sample 1 tab in the Hall Coefficient dialog box figure 5 9 to set the mea surement parameters for a sample wired to channel 1 on the Model 7100 Verify that the Measure check box is selected so that the sample is measured Then set the parameters as necessary Refer to section 5 3 2 3 to review how to set the parameters e Select the Sample 2 tab in the Hall Coefficient dialog box to set the measurement param eters for a sample wired to channel 2 on the Model 7100 Verify that the Measure check box is selected so that the sample is measured Then set the parameters as necessary Refer to section 5 3 2 3 to review how to set the parameters Notice that one seguence measurement can measure two samples The system measures sample 1 then it measures sample 2 5 14 PPMS AC Transport Option User s Manual Rev D 1 Ouantum Design October 15 2003 Chapter 5 Measurements Section 5 3 ACT Measurements ACT Hall Coefficient x Sample 1 Sample 2 PPMS Data IV Measure Amplitude foo ma M Constant Current Mode Eie 1000 Hz T Small Coefficients Mode Duration o1 Se Always Autorange C Sticky Autorange C Fixed Gain E Y F Figure 5 9 S
109. tic plot of the measurement The Status panel in the control center summarizes the measurement results The Critical Current dialog box displays the results from the last critical current measurement as well as the temperature magnetic field and sample position used during the measurement 2 Examine the diagnostic plot of the measurement in the Waveform tab This plot shows you whether the sample was read and roughly indicates how effective the measurement was 3 Select the Save button to save the results of the measurement to the specified data file or files You must select Save in order to save the data In addition to the critical voltage that is defined in the measurement dialog there is also a safety voltage limit that cannot be exceeded during critical current measurements This is an internal parameter related to the critical voltage and the A D converter range used to measure that voltage defined by Vsarety Veritica 20 of range The measurement is automatically aborted if the safety voltage is reached The percent of range above V qriticai that defines the safety voltage may be adjusted by changing the Critical Current Hard Trip value in the Configure tab Refer to section 4 2 1 5 5 3 5 Taking Resistivity Measurements in Sequence Mode 5 For detailed information about creating and editing sequence files E and for a discussion about all standard PPMS sequence commands NOTE refer to the Physical Property Measurement System PPMS M
110. ting conditions the ACT software automatically detects the presence of the Helium 3 insert and limits measurements to 20 mA Nonetheless you should never purposely set a current larger than 20 mA in the event that the software does not properly detect the insert When the ACT system uses the Helium 3 insert four of the sample chamber wires must be dedicated to the Helium 3 system platform thermometer Only eight wires rather than the normal twelve are available for ACT measurements so only one sample can be measured at a time A special probe cable see figure 6 1 splits off the four thermometer wires that go to the user bridge board from the dedicated ACT wiring that goes to the Model 7100 AC Transport Controller Quantum Design PPMS AC Transport Option User s Manual Rev D 1 6 1 October 15 2003 Section 6 3 ACT Measurements with the Helium 3 System 6 3 6 3 1 Caution 6 2 Chapter 6 Operation with the Helium 3 System ACT Measurements with the Helium 3 System Please refer to the Physical Property Measurement System Helium 3 Refrigerator System User s Manual for complete instructions on handling and operating the PPMS Helium 3 system Measurement Setup 6 3 1 1 PREPARE FOR THE MEASUREMENT Avoid stressing the shaft of the Helium 3 refrigerator probe in any way while you are inserting the refrigerator probe into or removing it from the PPMS sample chamber The material out of which the probe shaft
111. tion The V pads must be shorted together on the ACT sample holder when making five wire Hall measurements The phosphor bronze wires on the rotator probe which contact the bottom of the PPMS probe and thus the probe head cannot carry the 2 A that the ACT system is capable of sourcing You must use only the leads designated for current 7 8 11 12 as noted in the Physical Property Measurement System Horizontal Rotator Option User s Manual Horizontal Rotators with serial numbers 001 010 do not have separate leads for current and should never have 100 mA passed through any leads k 14 V Vy V ciojn 0 CH2 ALI gt 2M V V I 8 10 9 CH2 N D RESISTIVITY ON CH 1 ON CH1 B M V le oo V V 9 CH2 7 5 WIRE HALL CH1 AND RESISTIVITY CH2 2 13 ve V V f IL s Co V V 0 9 CH2 7 RESISTIVITY ON CI CH1 c 12 5 2 14 V Vy V N it 7 10 9 CH2 C 5 WIR HALL CH1 B CH1 AN RESISTIVITY CH2 ALTERNATE 2i Figure 7 2 Sample Wiring Diagrams for the Horizontal Rotator Option Remember to turn off UserTemp when you remove the Horizontal Rotator probe from the sample chamber Refer to section 7 3 1 PPMS AC Transport Option User s Manual R
112. tor Vertical Rotator or Helium 3 Refrigerator option The ACT option includes three ACT sample pucks PPMS sample pucks are sold by Quantum Design as a separate package The surface of each ACT sample puck has a circuit board with labeled contact pads for convenient sample wiring on two separate channels figure 5 1 These soft gold plated pads allow either wire bonding or soldering When you use an ACT sample puck you wire the sample according to one of the diagrams in figure 5 1 For Hall coefficient measurements the wire arrangements shown in figure 5 1 yield the proper sign for the coefficient During all types of four wire measurements you attach only the V contact pad and leave the V contact pad floating However you must turn the balance potentiometer for the appropriate channel fully counterclockwise to 0 0 to select the V4 lead Failing to turn the pot fully counterclockwise may sacrifice measurement accuracy Five Wi i Four Wire Hall Coefficient HaC us ient E g TEE Measurement Channel 2 Ms nis ipn S and Resistivity I V Trace FSI and Critical Current E Measurement Channel 1 Figure 5 1 Wiring Examples for ACT Measurements Quantum Design PPMS AC Transport Option User s Manual Rev D 1 5 1 October 15 2003 Section 5 2 Chapter 5 Sample Mounting Procedures Measurements Section 1 3 1 also discusses technigues for connecting sample leads
113. tropic sample wiring for resistivity measurement 1 2 Averaging time for critical current measurement 1 7 5 11 Balance potentiometers adjusting for five wire Hall measurement 5 6 for four wire measurement 1 5 5 1 7 4 function 3 1 3 2 Bar shaped sample wiring for resistivity measurement 1 2 1 3 BNC connectors on Model 7100 3 1 3 2 Configure tab in AC Transport control center 4 6 Constant Current LED when lit 3 2 Constant current mode comparison with low impedance mode 3 2 drive source impedance in 3 3 maintaining current with 3 2 Critical current definition of 1 7 Critical current hard trip parameter 4 6 5 11 Index 1 October 15 2003 Index Critical current measurement description 1 7 5 11 in immediate mode 5 10 5 11 operating modes 4 1 5 3 parameters defining 5 10 5 11 safety voltage limit 5 11 saving data from 5 4 5 10 5 19 in sequence mode 5 17 5 19 with superconducting samples 5 10 as variant of resistivity measurement 1 2 wiring sample for See Resistivity measurement Wiring sample Cross sectional area of sample defining 4 4 4 8 4 9 Current Offset Adjustment potentiometer 3 4 Data files See Measurement data files Raw measurement data files Data file header See Measurement data files Header Data File tab in AC Transport control center 4 3 4 8 Diagnostic plots of ACT measurements examples of 4 5 Digital filtering 1 1 Electrical current operating modes
114. tructions 4 Insert the Helium 3 refrigerator probe into the sample chamber Refer to the Physical Property Measurement System Helium 3 Refrigerator System User s Manual for detailed instructions 6 3 1 3 START UP THE SOFTWARE Start up PPMS MultiVu if the application is not running 2 Activate the Helium 3 option in PPMS MultiVu Do the following a select Utilities Quantum Design Activate Option b click on Helium3 under the Available Options heading and then c select the Activate button 6 3 PPMS AC Transport Option User s Manual Rev D 1 October 15 2003 Section 6 3 Chapter 6 ACT Measurements with the Helium 3 System Operation with the Helium 3 System 3 Activate the ACT option in PPMS MultiVu Do the following a select Utilities Activate Option b click on AC Transport under the Available Options heading and then c select the Activate button Both the Helium 3 software and ACT software must be running before you can initiate a measurement 4 Initiate a Helium 3 system test by using PPMS MultiVu or the Model 6000 front panel to set an initial temperature for example 300 K The Helium 3 temperature control is activated on the first Temperature Set command The software checks out the Helium 3 system downloads any necessary configuration data to the Model 6000 console and begins controlling temperature 6 3 2 Performing Measurements Once the Helium 3 refrigerator probe is inserted in the sample cham
115. uence Command 5 ee eee eee rct te e nre a tr bte 5 14 5 3 6 2 Prepate for the Measu rem nt 45 5 1e d tede de ite tees 5 15 5 3 6 3 Null the Offset Volt ge 3 ne ee haue I de petiere e bb teg wines 5 15 5 3 6 4 Run the Sequence sc er ec eee e Hh d vb SEE MO e ees 5 16 5 3 7 Taking I V Curve Measurements in Sequence Mode sse enne enne 5 16 5 3 7 Create the Sequence Command 5 2 eite rette tip re Oe eere ipeo 5 16 3 372 Prepare for the Meas rem nt o societe Hetero a a e ee e testes 5 17 3 3 7 3 Run the Sequence 2 e t d eec e I D e E Ie ERI ERG o eR ECESE as 5 17 5 3 8 Taking Critical Current Measurements in Sequence Mode esee 5 18 5 3 8 1 Create the Sequence Command asic iarna a e E enne enne E nnne SS Sh Des Leis 5 18 5 3 8 2 Prepare for the Measurernent sis iia een om den op RUE eei Eden 5 19 23 3 8 5 Run th Sequence usted edo te ete te ente eds 5 19 ii PPMS AC Transport Option User s Manual Rev D 1 Quantum Design October 15 2003 Contents Table of Contents CHAPTER 6 Operation with the Helium 3 System 1 sss tette tnter tnnt 6 1 6 Introduction 5 oiee ie re ert Bra Ge RR SIR daca ves HE ROPA II D s RR TR IE 6 1 6 2 Overview of ACT Operation with the Helium 3 System eese enne enne 6 1 6 3 ACT Measurements with the Helium 3 System eese ener neen enne nennen 6 2 6 3 1 Measurement Setu
116. ultiVu Application User s Manual 5 3 5 1 CREATE THE SEQUENCE COMMAND Select a new or existing sequence file 2 Selectthe Resistivity measurement command which is in the Measurement Commands group in the sequence command bar and define the command as follows 5 12 PPMS AC Transport Option User s Manual Rev D 1 Quantum Design October 15 2003 Chapter 5 Section 5 3 Measurements ACT Measurements e Select the Sample 1 tab in the Resistivity dialog box figure 5 7 to set the measurement parameters Sample 1 Sample 2 PPMS Data for a sample wired to channel on the Model 7100 Verify that the Measure check box is selected so that the sample is measured Then Constant Current Mode set the parameters as necessary Frequency 1000 Hz Low Resistance Mode Refer to section 5 3 1 2 to review bun for Se Always Autorange how to set the parameters C Sticky Autorange C FixedGain 5 e Select the Sample 2 tab in the Resistivity dialog box to set the measurement parameters for a sample wired to channel 2 on Lancet Heb the Model 7100 Verify that the Figure 5 7 Sample 1 Tab in Dialog Box for Measure check box is selected so Defining Resistivity Measurement in Sequence that the sample is measured Then Mode set the parameters as necessary Refer to section 5 3 1 2 Notice that one sequence measurement can measure two samples The system measures sample 1 then it measures sample 2 dil eer ME EEAS Pat
117. ure A 3 on the following page illustrates the connections Table A 2 Connections from Sample to Model 7100 PUCK LEMO MODEL 7100 FUNCTION L3 c pee BE 9 e lem 7 a a a i MODEL 7100 s s pue ww tmo cese en EE DEDE 3 Quantum Design PPMS AC Transport Option User s Manual Rev D 1 A 3 October 15 2003 Section A 4 Appendix A Pinout Tables Connections Ports and Pinouts P5 Sample Voltage In Sample Puck Bottom We aos s d Grey Lemo Connector 2 JN 434 TAER Si et 4 3 i 8 Sample Tube zo ie 3 gt 8 3 Wiring WO B O Y Cable P1 Sample Current RY Lu Out Sample Interface Probe Head Model 7100 Rear Panel Bottom of Probe Figure A 3 Illustration of ACT sample connections Two V wires for each channel provide parallel paths to the Model 7100 and are tied together inside the Model 7100 You may also want to connect the corresponding solder pads at the sample end of the measurement circuit the dedicated ACT sample pucks do this for you Va and Vb also provide parallel paths but are on opposite ends of the voltage divider and therefore should not be tied together at the sample end A 4 PPMS AC Transport Option User s Manual Rev D 1 Quantum Design October 15 2003 Appendix A Connections Ports and Pinouts A 4 2 Drive Access and Monitor Connections Ouantum Design Table A 3 Drive Access and Monitor Connections 876543 21 OOOOOOOO OOOOOOO 151413 12 11 10 9 P2 Dr
118. voltage lead is included for each channel to help reject external flux Each positive lead is twisted with a negative lead and the negative voltage leads are tied together in the Model 7100 AC Transport Controller During five wire measurements these negative voltage leads should also be tied together at the sample holder by connecting the two solder pads so that they function as intended The ACT sample pucks supplied with the ACT option automatically connect these solder pads During four wire measurements you connect only one positive voltage lead to the sample You may float the other positive lead but you must turn the Balance potentiometer for the appropriate channel completely in one direction or the other Turn the potentiometer fully counterclockwise to 0 0 to select the V lead and fully clockwise to 10 0 to select the Vy lead Failing to turn the potentiometer either fully clockwise or counterclockwise may result in a loss of accuracy 1 3 2 2 HARMONIC DETECTION During Hall coefficient measurements the detected second and third harmonics of the response signal voltage are reported in dB referenced to the fundamental response signal voltage This information can be related to nonlinearities in the sample but it frequently indicates the amount of noise encountered during the measurement The second and third harmonic contribution is usually less than 50 dB for a clean measurement and is larger when looking at very small sig
119. w of the ACT Software Software 4 6 4 2 1 5 CONFIGURE TAB Commands in the Configure tab run a hardware self test or change certain system settings Hardware self test commands and test results are in the Self Test panel Configurable settings are in the Settings panel AC Transport Control Center OE x Install Data File Sample 1 Sample 2 Waveform Configure Self Test Settings Auto Check on Startup Critical Current Iv Guick Check Hard Trip o 00 Start Hardware Check Test Results Diagnostic Hall Coefficient E IV Curve Critical Current Status Measure complete Good Gain at 5000mY Range Figure 4 5 Configure Tab in AC Transport Control Center The Start button in the Self Test panel initiates a hardware self test If the Quick Check option is selected Start initiates a quick self test that looks for outright component failure or serious component degradation The quick test uses the on board calibration resistors to check the output drive and gains If the Quick Check option is not selected Start initiates a more comprehensive and lengthy self test that looks for subtle errors that occur when a component is malfunctioning slightly The comprehen sive self test takes several minutes to complete The Auto Check on Startup option prompts the system to perform the hardware self test every time the ACT option is activated in PPMS MultiVu By default the Quick Check opt
120. wait for the field to reach zero 2 Select CTRL gt 1 Interactive Control gt 8 Shutdown Mode from the Model 6000 front panel The PPMS enters shutdown mode 3 Use the switch on the front panel of the Model 6000 to turn off the Model 6000 Do not turn off the vacuum pump or any other electronics in the PPMS electronics cabinet 4 Remove all stray equipment from the top of the electronics cabinet 5 Remove the top of the electronics cabinet by lifting it up and off the cabinet Remove the Model 6000 top cover Refer to figure 2 1 and do the following a unscrew the two screws on the top rear of the Model 6000 and b slide the top cover towards the rear of the Model 6000 and out of the cover groove Work carefully while the cover is off the top of the Model 6000 and avoid dropping hardware inside the unit Any hardware dropped inside the Model 6000 must be retrieved before power may be restored to the Model 6000 PPMS AC Transport Option User s Manual Rev D 1 Quantum Design October 15 2003 Chapter 2 Installation Section 2 3 Installation Procedures gy Figure 2 1 Remove the top cover of the Model 6000 by removing the two screws and sliding the cover towards the back of the controller 10 11 12 13 14 15 16 17 Ouantum Design Unscrew the two rear panel screws that hold the blank aluminum plate around the P3 Option port on the rear of the Model 6000 and then remove the plate Note w
121. will save measurement data figure 4 2 If no data file has been selected the File Name and Capture Raw Data panels are blank The data file header contains file and sample property information that is defined when the data file is created Information written to the data file header cannot be subsequently changed in PPMS MultiVu The file information that can be written to the header consists of the title assigned to the graph view of the data file The sample property information consists of the sample s material and voltage lead separation and the cross sectional area through which the current passes All information written to the header appears in the INFO declarations in the header It is extremely important that you define the correct voltage lead separation and cross sectional area for the current A when you create a data file The system uses whatever values are specified for these two parameters in order to calculate the sample resistivity and the Hall coefficient If you are concerned about entering incorrect values into the data file header use a value of 1 The results written to the data file header are then resistance and Hall resistance rather than resistivity and Hall coefficient because these values are calculated by multiplying the resistance by a factor of The ACT software automatically records the following data for every measurement time PPMS status code system temperature magnetic field sample position or

PPMS ACT Manual - Materials Research Laboratory at UCSB

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