CN101369010A - Automatized magnetic transportation measuring system using phase lock amplifying technology - Google Patents
Automatized magnetic transportation measuring system using phase lock amplifying technology Download PDFInfo
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- CN101369010A CN101369010A CNA2008102002129A CN200810200212A CN101369010A CN 101369010 A CN101369010 A CN 101369010A CN A2008102002129 A CNA2008102002129 A CN A2008102002129A CN 200810200212 A CN200810200212 A CN 200810200212A CN 101369010 A CN101369010 A CN 101369010A
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Abstract
The invention designs an automatic magneto-transport measurement system by using the phase lock amplification technology, which is used to accurately measure the characters related to electric transport of the material in low temperature and high magnetic field, such as measuring magnetoresistance shock, Hall Effect and the like. The system mainly comprises a standard Hall plate sample, a cooled cryostat and temperature control device, a magnet and a magnet control device, two phase lock amplifiers, a current supply, a reverse cut-off circuit, a voltage supply, a GPIB control card and a computer. The measurement material is made into a standard Hall plate sample, the computer is connected with each instrument through the GPIB bus, program is used to control each instrument to perform the automatic measurement, display the measurement results in real time, and store the measurement results as a data file. The system has the advantages that: 1. compared with the DC magneto-transport measurement, the system can use tittle measurement current to perform the magneto-transport measurement, and reduce adverse effects caused by big current and improve precision of the measurement; and 2. the system can automatically change the grid voltage and magnetic field, and the (grid voltage)-(magnetic field) phase map can be given within one measurement.
Description
Technical field
The present invention relates to the technology under the low temperature high-intensity magnetic field material electricity transport property measured, specifically refer to a kind of automatized magnetic transportation measuring system that uses phase lock amplifying technology, it is applicable to that mainly semiconductor material electricity under the profound hypothermia high-intensity magnetic field transports the accurate measurement of quantum effect.
Background technology
In the physical study process of semiconductor material and device, it is a kind of important and direct research means that magnetic transports measurement always.Under different temperature and magnetic field condition, classical and two processes of quantum of electricity transport property experience.By changing external conditions such as temperature, magnetic field, not only can obtain fundamental physical quantities such as carrier concentration in the sample and mobility, can also study some quantum physics phenomenons that under extreme conditions (profound hypothermia, high-intensity magnetic field) relates to carrier transport, for example magnetic resistance concussion, quantum Hall effect.By the research that semiconductor material quantum magnetic is transported, electron interaction, anti-weak local effect or the like between further analysis of material energy level distribution, electron spin division, different sub-band.
Present most of magnetic transports measurement and all is based on dc system, added current ratio big (generally in μ A magnitude) on sample when this just requires to test, when temperature is higher (more than the 77K), this influence to whole test is little, but reduction (4.2K is following) along with temperature, the heating effect of big electric current is more and more obvious, has brought bigger error to measurement; Owing to the restriction of direct current measurement, if it is too little to measure electric current, the precision of measurement just can't guarantee, so direct current measurement is difficult to realize high precision under profound hypothermia simultaneously.In addition, when sample has gate electrode, often wish that the electricity when acquisition grid voltage and magnetic field change continuously transports measurement result, thereby obtain grid voltage-magnetic field phasor.General measuring system is merely able to write down electricity and transports measurement result in autoscan grid voltage or magnetic field, therefore measuring flow process is manual adjustment grid voltage scanning magnetic field or manual adjustment field scan grid voltage.When needed grid voltage, when magnetic field point is a lot, this semi-automatic measuring mode just seems pretty troublesome.
Summary of the invention
Purpose of the present invention is exactly to solve direct current magnetic to transport measurement precision under profound hypothermia high and realize the automatic measurement of grid voltage-magnetic field phasor.Here it should be explicitly made clear at this point that the grid voltage of indication of the present invention-magnetic field phasor measurement is under certain temperature, sample grid voltage V
gWith magnetic field B respectively at certain limit [V
1, V
n] and [B
1, B
n] the interior variation, at each (V
g, B) all measure the longitudinal voliage and the lateral voltage of Hall Plate sample, obtain at [V thus
1, V
n], [B
1, B
n] the interior grid voltage of scope-magnetic field phasor.
The present invention has designed a kind of automatized magnetic transportation measuring system that uses phase lock amplifying technology, has realized that the accurate magnetic under the profound hypothermia transports the automatic measurement of measurement and grid voltage-magnetic field phasor.In view of the restriction of direct current measurement precision, the present invention adopts phase lock amplifying technology, uses alternating current and lock-in amplifier to carry out magnetic and transports measurement, and it is very little (generally 10～10 to measure electric current
2The nA magnitude), the heating effect of (below the 4.2K) is very little when profound hypothermia, has improved the accuracy of measuring greatly.
Technical solution of the present invention is as follows:
Measuring system comprises: standard Hall Plate sample 101, terminal box 102, cooled cryostat 103 and attemperating unit 104, magnet 105 and magnetic control means 106, two stand locks send out device 107 and 108 mutually big, current source 109, oppositely cut-off circuit 110, voltage source 111, GPIB control card 112, computing machine 113.
In the cooled cryostat 103 sample chamber is arranged, guarantee that specimen is temperature required.If magnet has special requirement to temperature, require to be operated in liquid helium temperature as superconducting magnet, magnet also should be placed in the cooled cryostat to guarantee working temperature so.Refrigerating plant or refrigerant liquid are arranged in the cooled cryostat, and heating arrangement is equipped with temperature control equipment 104, and the temperature of sample chamber can independently be adjusted or keep to attemperating unit 104.
Two stand lock phase amplifiers 107 and 108 are measured longitudinal voliage (between C-D or between F-G) and lateral voltage (between C-G or between F-D) respectively.According to phase-locked amplification principle, measurement needs reference signal, and reference signal and measuring-signal should same frequency and constant phase difference, so lock-in amplifier should have internal oscillator, can lock the reference signal of outside input, perhaps inner generation reference signal is also exported to other surveying instruments.In the present invention, a stand lock phase amplifier internal oscillator produces reference signal, and exports to another stand lock phase amplifier, exports to reverse cut-off circuit (introduce in detail and see below) simultaneously, makes measuring-signal and reference signal lock.In addition, two stand lock phase amplifiers 107 and 108 should have gpib interface, make computing machine can control it and measure and obtain measurement data.
GPIB card 112 provides gpib bus for computing machine 113, and computing machine is all finished by gpib bus with communicating by letter of each instrument.
The control maincenter of computing machine 113 for measuring controlled whole measuring process according to the program that weaves, and stores and the demonstration measurement result.
Fig. 3 is seen in connection between each instrument of measuring system.Hall Plate sample 101 is placed in the cooled cryostat 103, and attemperating unit 104 is connected with cooled cryostat 103, control sample chamber temperature.If 105 pairs of temperature of magnet have specific (special) requirements, so magnet 105 is placed cooled cryostat 103, otherwise magnet 105 places outside the Dewar 103.No matter magnet 105 where, will guarantee that all sample 101 is in field region.Magnetic control means 106 links to each other controlling magnetic field with magnet 105.Sample 101 each electrodes link to each other with terminal box 102 different ports by lead-in wire.By terminal box 102 ports, voltage source 111 is connected (grid voltage is provided) with sample 101B-E electrode or H-E electrode, oppositely (provide and measure electric current) is provided with the A-E electrode cut-off circuit 110 output terminals, lock-in amplifier 107 is connected (measurement longitudinal voliage) with C-D electrode or F-G electrode, lock-in amplifier 108 is connected (measurement lateral voltage) with C-G electrode or F-D electrode.Lock-in amplifier 107 internal oscillators produce reference signal, and its output terminal links to each other with the input end of lock-in amplifier 108, also link to each other with reverse cut-off circuit 110 reference signal input ends simultaneously.Current source 109 links to each other with reverse cut-off circuit 110 DC current input ends.Magnetic control means 106, voltage source 111, current source 109, lock-in amplifier 107 and lock-in amplifier 108 all link to each other with computing machine 113 by GPIB card 112.
Computer-controlled program can be controlled automatically and finish measuring process.Can obtain the data flow model of measuring system after measuring task analyzed, as Fig. 4.According to data flow model, design structure such as Fig. 5 of this program.Program is divided into grid voltage field scan pattern and magnetic field grid voltage scan pattern two big modules, and each module comprises measurement parameter input, measurement control, 3 submodules of measurement data output, wherein measures the core that controlling sub is a program.The submodule that the shared instrumentation of two big modules is relevant, other sub modular structures are similar but concrete composition is different.The control information and the data message that transmit between each submodule see description of drawings for details.Two big modules are two kinds of measurement patterns of corresponding grid voltage-magnetic field phasor respectively: grid voltage field scan pattern is for setting grid voltage V respectively
g=V
1, V
2, V
3, V
n, when different grid voltages, at [B
1, B
n] scope interscan magnetic field, measure vertical and horizontal voltage simultaneously, finish [V at last
1, V
n], [B
1, B
n] measurement of grid voltage in the scope-magnetic field phasor; Magnetic field grid voltage scan pattern is for setting magnetic field intensity B=B respectively
1, B
2, B
3, B
n, when different magnetic field intensitys, at [V
1, V
n] scope interscan grid voltage, measure vertical and horizontal voltage simultaneously, finish [B at last
1, B
n], [V
1, V
n] measurement of grid voltage in the scope-magnetic field phasor.
According to program structure diagram and measurement control method, program flow diagram (Fig. 6) mainly is to measuring the detailed design of control module in the program structure diagram, the clear detailed process of measuring of having described.User interface (input panel, demonstration in real time) part can design according to used development system characteristics; The instrument driving is write according to the instrument instructions of selecting for use or is directly used instrument to carry driving; The GPIB card drives and uses it to carry driving; File is preserved part and is designed according to required file layout.In the description of drawings in detail note the emphasis step in the process flow diagram.With data flow diagram, program structure diagram, program flow diagram and be illustrated as foundation, can use high-level [computer (as C++, Labview, Basic etc.) to work out out computer-controlled program.
Test process of the present invention is as follows:
1, finish sample 101 and prepare, cooled cryostat 103 is prepared, and demarcates reverse cut-off circuit output current root-mean-square value, demarcates the corresponding relation of exciting current and magnetic field intensity, connects each testing tool and places sample by Fig. 3.
2, adjust attemperating unit 104, make sample 101 reach and keep required probe temperature.
3, the operation computer-controlled program is selected grid voltage-magnetic field phasor measurement pattern, and input current source parameter, field scan parameter, grid voltage sweep parameter, lock-in amplifier parameter, file are preserved the position.If sample do not need grid voltage, then can select grid voltage field scan pattern, be made as 1 but grid voltage counted, initial value, stop value all are made as 0, magnetic field is set again gets final product; If sample does not need magnetic field yet, then further magnetic field initial value, stop value all are made as 0, sweep speed is any.If sample do not need magnetic field, then can select magnetic field grid voltage scan pattern, be made as 1 but magnetic field counted, initial value, stop value all are made as 0, grid voltage is set again gets final product.Click the beginning button, the procedure auto-control measuring process is preserved measurement result automatically after measurement is finished.
4, can change temperature, reset measurement parameter, carry out new measurement.
5, after measurement finishes, take out sample, remove line, playback cooled cryostat and each testing tool.
The present invention has following advantage: the enough Weak currents of energy are (generally 10～10
2The nA magnitude) magnetic that carries out transports measurement, reduces the adverse effect that big electric current brings, and has realized that accurate electricity transports measurement under the profound hypothermia high-intensity magnetic field; Automatically measure grid voltage-magnetic field phasor and write down experimental data and real-time video data figure, measuring process is directly perceived and automaticity is high.
Description of drawings
Fig. 1: Hall Plate sample structure synoptic diagram.
Fig. 2: reverse cut-off circuit synoptic diagram.
Fig. 3: the automatized magnetic transportation measuring system structural representation that uses phase lock amplifying technology;
101, standard Hall Plate sample; 102, terminal box; 103, cooled cryostat; 104, attemperating unit; 105, magnet; 106, magnetic control means; 107, lock-in amplifier; 108, lock-in amplifier; 109, current source; 110, reverse cut-off circuit; 111, voltage source; 112, GPIB control card; 113, computing machine.
Fig. 4: computer-controlled program data flow diagram;
(1) data stream clauses and subclauses
(annotate: data unit is the acquiescence unit from instrument to experimental data 1=grid voltage+exciting current+longitudinal voliage+lateral voltage.)
(annotate: electric current is the root-mean-square value of reverse cut-off circuit output current to experimental data 2=electric current+grid voltage+magnetic field intensity+longitudinal voliage+lateral voltage, and data unit is a program setting unit.)
(annotate: data are the form of chart to chart=electric current+grid voltage+magnetic field intensity+longitudinal voliage+lateral voltage.)
(2) file entries
Experimental data formation: { grid voltage+exciting current+longitudinal voliage+lateral voltage } (annotate: data unit is the acquiescence unit from instrument, and formation is a dynamic queue, and the experimental data of obtaining is advanced tail of the queue, and the experimental data of processing goes out head of the queue)
The experimental data file: electric current+(grid voltage | magnetic field intensity)+(magnetic field intensity | grid voltage)+longitudinal voliage+lateral voltage } (annotate: electric current is the root-mean-square value of reverse cut-off circuit output current, and data unit is a program setting unit.)
(3) little explanation
Obtain experimental data: control instrument is measured, and obtains experimental data from instrument, writes formation.
Processing queue data: from formation, take out experimental data, be converted into the unit that needs; Exciting current is converted to corresponding magnetic field intensity; Obtain output current from current source, be converted into the root-mean-square value of reverse cut-off circuit output current.
Video data: experimental data is shown as diagrammatic form in real time, makes things convenient for the experimenter to monitor.
Storage data: convert experimental data to suitable format and save as data file.
Fig. 5: computer-controlled program modular structure figure;
Grid voltage field scan pattern is identical with magnetic field grid voltage model program general structure, more shared modules, though non-shared module function class of the same name is seemingly, but the internal structure difference is two different modules.Transmission information between the module, English alphabet sign be control information, Digital ID be data message.
(1) control information
A, instrument parameter comprise: grid voltage initial value, stop value, grid voltage are counted and other voltage source call parameters; Magnetic field initial value, stop value, field scan speed and other magnetic control means call parameters; Two lock-in amplifiers voltage range separately, time constant, reference signal frequency and other lock-in amplifier call parameters; Current source output valve and other current source call parameters; Data file is preserved position, title, file specification etc.
B, the correct instrument parameter in inspection back, magnetic field initial value, stop value, the field scan rate transition becomes corresponding exciting current initial value, stop value, excitation speed.
C, initialization and instrument are provided with order.
D, E, F, G are respectively the order of Control current source 109, voltage source 111, lock-in amplifier 107 or lock-in amplifier 108, magnetic control means 106.
H, J, K, L are respectively that driven with current sources, voltage source drive, lock-in amplifier drives, magnetic control means drives the order that sends by the GPIB card.
M, obtain in the experimental data process operational order to instrument.
N, close the instrument order.
P, instrument parameter comprise: magnetic field initial value, stop value, magnetic field are counted and other magnetic control means call parameters; Grid voltage initial value, stop value, grid voltage are counted and other voltage source call parameters; Two lock-in amplifiers voltage range separately, time constant, reference signal frequency and other lock-in amplifier call parameters; Current source output valve and other current source call parameters; Data file is preserved position, title, file specification etc.
Q, the correct instrument parameter in inspection back, magnetic field initial value, stop value, the field scan rate transition becomes corresponding exciting current initial value, stop value, excitation speed.
R, initialization and instrument are provided with order.
S, obtain in the experimental data process operational order to instrument.
(2) data message
1,2,3,4 is respectively measurement data or the status information that current source 109, voltage source 111, lock-in amplifier 107 or lock-in amplifier 108, magnetic control means 106 return.
5, one group of measurement data returning: current source output valve, voltage source output valve, exciting current, longitudinal voliage, lateral voltage.
6, unit is for setting the measurement data of unit: electric current (the oppositely root-mean-square value of cut-off circuit output current), grid voltage, magnetic field intensity, longitudinal voliage, lateral voltage.
7, a collection of measurement data that grid voltage point is corresponding: electric current+grid voltage+{ magnetic field intensity+longitudinal voliage+lateral voltage }.
8, arrangement is the measurement data of required file layout: file specification+electric current+{ grid voltage+{ magnetic field intensity+longitudinal voliage+lateral voltage } }.
9, one group of measurement data returning: current source output valve, exciting current, voltage source output valve, longitudinal voliage, lateral voltage.
10, unit is for setting the measurement data of unit: electric current (the oppositely root-mean-square value of cut-off circuit output current), magnetic field intensity, grid voltage, longitudinal voliage, lateral voltage.
11, a collection of measurement data that magnetic field point is corresponding: electric current+magnetic field intensity+{ grid voltage+longitudinal voliage+lateral voltage }.
12, arrangement is the measurement data of required file layout: file specification+electric current+{ magnetic field intensity+{ grid voltage+longitudinal voliage+lateral voltage } }.
Fig. 6: computer-controlled program process flow diagram;
Below mentioned operation (as sending order, reading of data etc.) to instrument, all be to realize by the driver of each instrument, the bottom then is to drive and the instrument realization is communicated by letter by the GPIB card.Instrument drivers write instructions that please refer to used instrument or the driver that directly uses instrument to carry, the GPIB card drives and uses it to carry driving.
Note:
1, input parameter is with the control information A among Fig. 5.
2, inspection apparatus parameter correctness, simultaneously with magnetic field initial value, stop value, the field scan rate transition becomes corresponding exciting current initial value, stop value, excitation speed; Calculate the grid voltage spacing value between the grid voltage point.
3, send initialization command, initialization current source 109, voltage source 111, magnetic control means 106, lock-in amplifier 107 and lock-in amplifier 108 are provided with each instrument according to the parameter in the note 1, make it be in the duty of test request.
4, send order to current source 109, the steady current of appointment in the output note 1.
5, setting value or measured value are transformed to required unit, if the current source output current value then is transformed to it reverse cut-off circuit output current root-mean-square value; If exciting current then is transformed to it corresponding magnetic field intensity.After the conversion data are deposited in temporary array correspondence position.
6, temporary array 1 is a memory object, and temporary transient storage of measurement data is with the faster procedure travelling speed, and its data structure is: electric current+grid voltage+{ magnetic field intensity+longitudinal voliage+lateral voltage }.
7, send order to voltage source 111, the steady voltage of output appointment.
8, send order to magnetic control means 106, select scan pattern, exciting current initial value, stop value are set, excitation speed sends order again, begins scanning.
9, reading, cycle of treatment are two parallel circulations, and they constitute the producer/consumer's structure.The reading image data (being the producer) constantly that circulates, cycle of treatment is deal with data (being the consumer) constantly, comes Data transmission by formation between the circulation.Formation is two data bufferings between the circulation, and such structure makes data processing can not drag slow data acquisition.
10, data queue 1 is a memory object, is dynamic queue.A unit is added on tail of the queue when entering formation, when read a unit from head of the queue after, delete this element in the formation, and next unit becomes head of the queue.The data structure of a unit is: exciting current+longitudinal voliage+lateral voltage.
11, can in the reading circulation, add time-delay to adjust rate of reading.
12, send the order of reading exciting current, longitudinal voliage, lateral voltage respectively to magnetic control means 106, lock-in amplifier 107, lock-in amplifier 108, receive this three measurement data subsequently again respectively.
13, with the exciting current, longitudinal voliage, the lateral voltage that receive, deposit data queue 1 in as a unit.
14, according to employed development system, select suitable manner to show measurement data in real time, preferably can use the form of chart.
15, whether equal the magnetic field end point values according to the magnetic field intensity that reads and judge, as equal then loop termination and stop element 1 is changed into stopping simultaneously, as not waiting then circulation continuation.
16, file layout as required is added into data file 1 with the file specification in temporary array 1 and the note 1 according to filename in the note 1 and path, empties the data except that electric current in the temporary array 1 afterwards.
17, comprise measurement data under a plurality of grid voltage points in the data file 1, its data structure is: file specification+electric current+{ grid voltage+{ magnetic field intensity+longitudinal voliage+lateral voltage } }.
18, whether equal the grid voltage judgement of counting according to period, as equal then loop termination, circulation continues as not waiting then, and next grid voltage value increases a spacing value on the basis of currency.
19, send order to current source 109, voltage source 111, magnetic control means 106, lock-in amplifier 107 and lock-in amplifier 108, make its state of deactivating, standby.
20, input parameter is with the control information P among Fig. 5.
21, inspection apparatus parameter correctness converts magnetic field initial value, stop value to corresponding exciting current initial value, stop value simultaneously; Magnetic field spacing value between the calculating magnetic field point; Calculate the grid voltage spacing value between the grid voltage point.
22, temporary array 2 and temporary array 1 are similar, and its data structure is: electric current+magnetic field intensity+{ grid voltage+longitudinal voliage+lateral voltage }.
23, send order to magnetic control means 106, select fixed mode, be set to the exciting current and the maintenance of appointment.
24, data queue 2 is similar with data queue 1, and the data structure of a unit is: grid voltage+longitudinal voliage+lateral voltage.
25, can in the reading circulation, add time-delay to adjust rate of reading.
26, send the order of reading longitudinal voliage, lateral voltage respectively to lock-in amplifier 107, lock-in amplifier 108, receive this two measurement data subsequently again respectively.
27, with longitudinal voliage, the lateral voltage of grid voltage setting value and reception, deposit data queue 2 in as a unit.
28, whether equal the grid voltage judgement of counting according to period, as equal then loop termination and stop element 2 is changed into stopping simultaneously, circulation continues as not waiting then, and next grid voltage value increases a spacing value on the basis of currency.
29, file layout as required is added into data file 2 with the file specification in temporary array 2 and the note 20 according to filename in the note 20 and path, empties the data except that electric current in the temporary array 2 afterwards.
30, comprise measurement data under a plurality of magnetic field points in the data file 2, its data structure is: file specification+electric current+{ magnetic field intensity+{ grid voltage+longitudinal voliage+lateral voltage } }.
31, whether equal the magnetic field judgement of counting according to period, as equal then loop termination, circulation continues as not waiting then, and next field strength values increases a spacing value on the basis of currency.
Fig. 7: the user interface of grid voltage field scan pattern.
Fig. 8: the user interface of magnetic field grid voltage scan pattern.
Embodiment
Provide an example preferably of the present invention according to summary of the invention and description of drawings below, further specify the technology of the present invention details, architectural feature and functional characteristics in conjunction with example.But this example does not limit the scope of the invention, and conforming with the example of describing in summary of the invention and the description of drawings all should comprise within the scope of the present invention.
Measuring system comprises following ingredient:
Cooled cryostat 103 and magnet 105 adopt Oxford superconducting magnet low-temperature measurement system.The annular superconducting magnet is immersed in the liquid helium, and the protection of vacuum layer and liquid nitrogen layer arranged outward.The highest magnetic field intensity that 17T can be provided of superconducting magnet is by magnetic control means 106 controls.Magnetic control means 106 has gpib interface, can directly set magnetic field intensity by computing machine 113, or sets scanning magnetic field after magnetic field starting point, terminal point, the sweep speed, also can be directly field strength values up till now, do not need to demarcate again and change.The sample chamber is in toroidal magnet central authorities, and attemperating unit 104 may command main helium pools pour into liquid helium to the sample chamber.The sample chamber links to each other with aspiration pump, a built-in resistive heater, temperature can be regulated in the scope of 1.2～300K, and 4.2K is following to be obtained by liquid helium decompression in the sample chamber, 4.2K more than obtain by resistance wire heating in the sample chamber, these can be by attemperating unit 104 independent controls.
Lock-in amplifier 107 and lock-in amplifier 108 all adopt the SR830 type lock-in amplifier of Stanford Research Systems.SR830 can measure alternating voltage, and (2nV～1V) and current signal (2fA～1 μ A), internal oscillator can produce reference signal, also can receive the outside reference signal of locking.SR830 also has gpib interface, can pass through computer controlled measurement.
Two Keithley 2400 Source Meter, one as 109, one of current sources as voltage source 111.Keithley 2400 can output dc voltage (0～20V, minimum interval 5 μ V), electric current (0～1A, minimum interval 50pA), has gpib interface, and computing machine 113 can be controlled its output, measuring operation.
Oppositely cut-off circuit 110 is bought corresponding electronic devices and components and circuit version according to shown in Figure 2, and welding gets final product voluntarily.The concrete parameter of components and parts can be determined according to measurement size of current, reference signal amplitude.According to the method in the summary of the invention, demarcate the corresponding relation of current source output valve and reverse cut-off circuit output current root-mean-square value, according to this relation, computer-controlled program can be changed this two values automatically.
After being ready to instrument according to each instrumentation rules, connect system according to Fig. 3, concrete grammar has detailed description in summary of the invention, no longer repeats herein.
Open each instrument, adjust attemperating unit 104, reach and measure temperature and maintenance.Open computer-controlled program, import corresponding measurement parameter, click start button, the procedure auto-control instrument is measured, and shows measurement data with diagrammatic form in real time in the measurement, after measurement is finished experimental data is saved as data file.Afterwards, readjust attemperating unit 104, import corresponding measurement parameter, carry out new measurement.After measurement is finished, take out sample, powered-down, each instrument playbacks.
Claims (9)
1. automatized magnetic transportation measuring system that uses phase lock amplifying technology, it comprises: standard Hall Plate sample (101), terminal box (102), cooled cryostat (103) and attemperating unit (104), magnet (105) and magnetic control means (106), phase-lockedly send out device (107) big, lock-in amplifier (108), current source (109), oppositely cut-off circuit (110), voltage source (111), GPIB control card (112), computing machine (113), it is characterized in that: sample (101) is placed in the cooled cryostat (103), is in the field region; Attemperating unit (104) is connected with cooled cryostat (103); Magnet (105) places outside cooled cryostat (103) or the cooled cryostat (103), and magnetic control means (106) links to each other with magnet (105); Sample (101) A～H electrode links to each other with each port of terminal box (102) by lead-in wire; By terminal box (102) port, voltage source (111) is connected with sample (101) B-E electrode or H-E electrode, oppositely cut-off circuit (110) output terminal is connected with the A-E electrode, lock-in amplifier (107) is connected with C-D electrode or F-G electrode, and lock-in amplifier (108) is connected with C-G electrode or F-D electrode; Lock-in amplifier (107) reference signal output terminal links to each other with the reference signal input end of lock-in amplifier (108), also links to each other with reverse cut-off circuit (110) reference signal input end simultaneously; Current source (109) links to each other with reverse cut-off circuit (110) DC current input end; Magnetic control means (106), voltage source (111), current source (109), lock-in amplifier (107) and lock-in amplifier (108) all link to each other with computing machine (113) by GPIB card (112).
2. a kind of automatized magnetic transportation measuring system that uses phase lock amplifying technology according to claim 1 is characterized in that: said cooled cryostat has the sample chamber in (103), magnet lay down location, refrigerating plant or refrigerant liquid, heating arrangement; Be equipped with the independent temperature of adjusting or keeping the sample chamber of attemperating unit (104).
3. a kind of automatized magnetic transportation measuring system that uses phase lock amplifying technology according to claim 1 is characterized in that: said magnet (105) is an electromagnet, and by magnetic control means (106) control, magnetic control means (106) has gpib interface.
4. a kind of automatized magnetic transportation measuring system that uses phase lock amplifying technology according to claim 1 is characterized in that: said lock-in amplifier (107) and lock-in amplifier (108) energy measurement voltage have internal oscillator and gpib interface.
5. a kind of automatized magnetic transportation measuring system that uses phase lock amplifying technology according to claim 1 is characterized in that: said current source (109) is a DC source, has gpib interface.
6. a kind of automatized magnetic transportation measuring system that uses phase lock amplifying technology according to claim 1, it is characterized in that: said reverse cut-off circuit (110) input dc power stream and ac voltage signal, the alternating current of output and ac voltage signal same frequency and constant phase difference.
7. a kind of automatized magnetic transportation measuring system that uses phase lock amplifying technology according to claim 1 is characterized in that: said voltage source (111) is a direct voltage source, has gpib interface.
8. a kind of automatized magnetic transportation measuring system that uses phase lock amplifying technology according to claim 1, it is characterized in that: the control maincenter of computing machine (113) for measuring, GPIB card (112) provides gpib bus for computing machine (113), and computing machine (113) is communicated by letter by gpib bus with each instrument.
9. automatized magnetic transportation measuring method of using phase lock amplifying technology, it is characterized in that: it has following computer controlled automatic measuring process:
A, grid voltage field scan pattern: open program, the input measurement parameter is checked the parameter correctness; The initialization instrument; Control current source (109) output current, current value deposits internal memory in; One-level circulation beginning; Control voltage source (111) output voltage, magnitude of voltage deposits internal memory in; Control magnetic control means (106) scanning magnetic field, two parallel secondary circulation beginnings; The circulation of secondary is from magnetic control means (106), and lock-in amplifier (107) and lock-in amplifier (108) read measurement data and deposit formation in, and another secondary circulation is from formation taking-up data, shows in real time and deposits internal memory in; After field scan is finished, two secondary loop ends; The data of preserving in the internal memory are write data file, empty internal memory; Finish then the one-level circulation as all grid voltage point measurements and stop, otherwise restart the one-level circulation; Control instrument enters holding state; Quit a program;
B, magnetic field grid voltage scan pattern: open program, the input measurement parameter is checked the parameter correctness; The initialization instrument; Control current source (109) output current, current value deposits internal memory in; One-level circulation beginning; Control magnetic control means (106) output fixed magnetic field, magnetic field intensity deposits internal memory in; Two parallel secondary circulation beginnings; A secondary cycle control voltage source (111) output voltage, read measurement data from lock-in amplifier (107) and lock-in amplifier (108), magnitude of voltage and measurement data deposit formation in, and the circulation of another secondary is taken out data from formation, show in real time and deposit internal memory in; After all grid voltage point measurements are finished, two secondary loop ends; The data of preserving in the internal memory are write data file, empty internal memory; Finish then the one-level circulation as all magnetic field point measurements and stop, otherwise restart the one-level circulation; Control instrument enters holding state; Quit a program.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2008102002129A CN101369010B (en) | 2008-09-22 | 2008-09-22 | Automatized magnetic transportation measuring system using phase lock amplifying technology and measurement method |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104614654A (en) * | 2013-11-04 | 2015-05-13 | 华东师范大学 | Automatic test system for testing multiple electrical parameters of semiconductor |
| CN105137125A (en) * | 2015-08-31 | 2015-12-09 | 电子科技大学 | Double-frequency multichannel synchronization detection method for electric domain imaging |
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| US6023139A (en) * | 1999-04-27 | 2000-02-08 | Tai E International Patent And Law Office | Brushless DC fan driver with an integral overall protection capability |
| CN1968002B (en) * | 2006-10-24 | 2012-05-23 | 北京航空航天大学 | A phase-lock steady speed control system of high speed permanent-magnetic brushless DC motor |
| CN201110876Y (en) * | 2007-10-23 | 2008-09-03 | 上海电缆研究所 | High-temperature superconduction material superconductivity test system |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104614654A (en) * | 2013-11-04 | 2015-05-13 | 华东师范大学 | Automatic test system for testing multiple electrical parameters of semiconductor |
| CN104614654B (en) * | 2013-11-04 | 2017-09-19 | 华东师范大学 | A kind of automatization test system of multichip semiconductor electrical parameter |
| CN105137125A (en) * | 2015-08-31 | 2015-12-09 | 电子科技大学 | Double-frequency multichannel synchronization detection method for electric domain imaging |
| CN105137125B (en) * | 2015-08-31 | 2018-11-13 | 电子科技大学 | A kind of double frequency multi-channel synchronous detection method for electricdomain imaging |
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