Thermal conductivity measurement system and thermal conductivity measurement method

Abstract

The present application relates to a thermal conductivity measurement system and a thermal conductivity measurement method. The system includes: a thermal structure, a constant current alternating current source, and a phase-locked amplifier, wherein the thermal structure includes a substrate, and the substrate is provided with a window; conductive connection terminals are provided at both ends of the sample to be tested, and two detection connection terminals are also provided on the sample to be tested, and the detection connection terminals are located between the conductive connection terminals, and the sample to be tested is mounted on the window of the substrate through the conductive connection terminals and the detection connection terminals; the constant current alternating current source is electrically connected to the conductive connection terminals, and the phase-locked amplifier is electrically connected to the detection connection terminals. The method can be used to pass a constant current to the sample to be tested through a constant current alternating current source and monitor the voltage of the phase-locked amplifier to lock the selected frequency. The sample to be tested is not limited to a macroscopic sample, avoiding the limitation and influence of the sample size on the thermal conductivity measurement. The three-measurement method is used to combine current and voltage to accurately calculate the thermal conductivity of the sample to be tested, thereby improving the accuracy of the thermal conductivity measurement of the material.

Description

Technical Field

[0001] The present application relates to the field of thermal conductivity measurement technology, and in particular to a thermal conductivity measurement system, a method for preparing a thermal structure, a thermal conductivity measurement method, an apparatus, a computer device, a computer-readable storage medium, and a computer program product. Background Art

[0002] Thermodynamic properties include thermal conductivity, specific heat and thermal expansion coefficient of materials. Thermal conductivity can provide quantitative information about the thermal conductivity of materials, which helps to evaluate parameters such as thermal conductivity, thermal conduction mechanism and thermal resistance of thermal interface. Thermal conductivity measurement can be used to understand the thermal conductivity of materials. Thermal conductivity measurement is very important for studying the thermal properties, thermal conduction mechanism and thermoelectric properties of materials. By studying the thermal conductivity of different materials, we can gain a deeper understanding of the crystal structure, molecular vibration mode, electronic structure and other characteristics of the materials, thus providing a deeper understanding of the properties of the materials.

[0003] Traditional technology mainly uses the complex structure of the material to construct a thermal gradient to complete the measurement of thermal conductivity. However, traditional technology is limited by the size of the sample, and the thermal conductivity measurement process is easily affected by signals in other directions, which interferes with the observation of the anisotropy of the material, thereby affecting the accuracy of the thermal conductivity measurement and is not conducive to improving the accuracy of the thermal conductivity measurement of the material. Summary of the invention

[0004] Based on this, it is necessary to provide a thermal conductivity measurement system, a method for preparing a thermal structure, a thermal conductivity measurement method, an apparatus, a computer device, a computer-readable storage medium and a computer program product that can improve the accuracy of thermal conductivity measurement of materials in response to the above technical problems.

[0005] In a first aspect, the present application provides a thermal conductivity measurement system, wherein the thermal conductivity measurement system is used to measure the thermal conductivity of a The thermal conductivity of the sample to be measured is measured by the measuring method. The system comprises: a thermal structure, a constant current alternating current source, and a phase-locked amplifier. The thermal structure comprises:

[0006] A substrate, wherein the substrate is provided with a window;

[0007] A sample to be tested, wherein two ends of the sample to be tested are provided with conductive connection ends, and the sample to be tested is also provided with two detection connection ends, wherein the two detection connection ends are located between the two conductive connection ends, and the sample to be tested is mounted on the window of the substrate through the two conductive connection ends and the two detection connection ends, and is thermally connected to the substrate through the conductive connection ends and the detection connection ends;

[0008] The constant current alternating current source is electrically connected to the two conducting connection terminals, and the phase-locked amplifier is electrically connected to the two detecting connection terminals.

[0009] In one embodiment, the system also includes an electrical structure, which includes a first pin, a second pin, a third pin and a fourth pin, the first pin is electrically connected to one of the two conductive connection ends, the second pin is electrically connected to the other of the two conductive connection ends, the third pin is electrically connected to one of the two detection connection ends, and the fourth pin is electrically connected to the other of the two detection connection ends.

[0010] In one embodiment, one of the two output terminals of the constant-current alternating current source is electrically connected to the first pin, and the other of the two output terminals of the constant-current alternating current source is electrically connected to the second pin.

[0011] In one embodiment, one of the two signal input terminals of the phase-locked amplifier is electrically connected to the third pin, the other of the two signal input terminals of the phase-locked amplifier is electrically connected to the fourth pin, and the reference signal input terminal of the phase-locked amplifier is electrically connected to the constant current AC current source.

[0012] In one of the embodiments, a sapphire sheet is disposed between the electrical structure and the thermal structure.

[0013] In one of the embodiments, the sapphire sheet is fixed to the electrical structure and the thermal structure respectively by silver glue.

[0014] In a second aspect, the present application further provides a method for preparing a thermal structure in the above-mentioned thermal conductivity measurement system, the method comprising:

[0015] The sample material was fixed to the substrate using deposited platinum;

[0016] Etching the sample material to form a sample to be tested on the substrate, wherein two ends of the sample to be tested are provided with conductive connection ends, and the sample to be tested is also provided with two detection connection ends, and the two detection connection ends are between the two conductive connection ends;

[0017] The substrate is etched to form a window on the substrate, so that the sample to be tested is mounted on the window of the substrate through the conductive connection end and the detection connection end, and is thermally connected to the substrate through the conductive connection end and the detection connection end.

[0018] In one embodiment, the sample to be tested has a length of 50-200 microns, a width of 10-20 microns, and a thickness of 1-4 microns.

[0019] In a third aspect, the present application further provides a thermal conductivity measurement method applied to the above-mentioned thermal conductivity measurement system, the method comprising:

[0020] Obtaining the current between two conductive connection terminals of the sample to be tested;

[0021] When the temperature of the sample to be tested is 3K, obtaining the voltage corresponding to the two detection connection terminals of the sample to be tested, the resistance between the two detection connection terminals of the sample to be tested, and the rate of change of the resistance with temperature;

[0022] The thermal conductivity of the sample to be tested is determined according to the current, the voltage, the resistance and the rate of change.

[0023] In one embodiment, the calculation expression of the thermal conductivity of the sample to be tested is expressed as:

[0024]

[0025] in, is the thermal conductivity, is the current, is the length of the sample to be tested, is the resistance, is the rate of change of resistance, is the triple frequency of the voltage, The voltage corresponding to the two detection connection terminals of the sample to be tested is obtained. is the cross-sectional area of ​​the sample to be tested.

[0026] In a fourth aspect, the present application also provides a thermal conductivity measuring device, comprising:

[0027] An acquisition module, used for acquiring the current between two conductive connection terminals of the sample to be tested;

[0028] A monitoring module, used for obtaining, when the temperature of the sample to be tested is 3K, the voltage corresponding to the two detection connection terminals of the sample to be tested, the resistance between the two detection connection terminals of the sample to be tested, and the rate of change of the resistance with temperature;

[0029] A determination module is used to determine the thermal conductivity of the sample to be tested according to the current, the voltage, the resistance and the rate of change.

[0030] In a fifth aspect, the present application further provides a computer device, wherein the computer device comprises a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the steps of the above method are implemented.

[0031] In a sixth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program implements the steps of the above method when executed by a processor.

[0032] In a seventh aspect, the present application further provides a computer program product, wherein the computer program product comprises a computer program, and when the computer program is executed by a processor, the steps of the above method are implemented.

[0033] The thermal conductivity measurement system, the method for preparing a thermal structure, the method for measuring thermal conductivity, the device, the computer equipment, the computer-readable storage medium and the computer program product use a constant-current alternating current source to pass a current into the sample to be measured through the two conductive connection terminals of the sample to be measured, and use a phase-locked amplifier to monitor the voltage between the two detection connection terminals of the sample to be measured through the two detection connection terminals of the sample to be measured. Since the sample to be measured is mounted on the window of the substrate through the two conductive connection terminals and the two detection connection terminals, and is thermally connected to the substrate through the conductive connection terminals and the detection connection terminals, the thermal connection only occurs at the detection connection terminals and the conductive connection terminals of the sample to be measured, and good thermal insulation is maintained. A constant current is passed through the constant-current alternating current source to the sample to be measured and the voltage at the selected frequency locked by the phase-locked amplifier is monitored. The sample to be measured is no longer limited to a macroscopic sample, and the limitation and influence of the sample size on the thermal conductivity measurement can be avoided. By using 3 The measurement method combines current and voltage to accurately calculate the thermal conductivity of the sample to be measured, thereby improving the accuracy of material thermal conductivity measurements. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments of the present application or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0035] Figure 1 is a top view of a thermal conductivity measurement system in one embodiment;

[0036] Figure 2 is a side view of a thermal conductivity measurement system in one embodiment;

[0037] Figure 3 is a side view of a thermal structure in one embodiment;

[0038] Figure 4 is a top view of a thermal structure in one embodiment;

[0039] Figure 5 is a schematic flow chart of a thermal conductivity measurement method in one embodiment;

[0040] Figure 6 A schematic diagram of a process for measuring thermal conductivity in one embodiment;

[0041] Figure 7 It is a schematic diagram of a voltage frequency-doubled signal changing with current in one embodiment;

[0042] Figure 8 It is a schematic diagram of a voltage triple frequency signal changing with current in one embodiment;

[0043] Fig. 9 is a schematic diagram of the variation of resistance and thermal conductivity with magnetic field strength in one embodiment;

[0044] Fig.10 is a structural block diagram of a thermal conductivity measuring device in one embodiment;

[0045] Fig.11 The figure is a diagram of the internal structure of a computer device in one embodiment.

[0046] The reference numerals and their meanings are as follows:

[0047] 101. substrate; 102. window; 103. sample to be tested; 104. conductive connection terminal; 105. detection connection terminal; 106. sapphire sheet; 107. first pin; 108. second pin; 109. third pin; 110. fourth pin; 111. circuit board. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0049] In the description of the present application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0050] In an exemplary embodiment, a thermal conductivity measurement system is provided. The thermal conductivity measurement system is used to measure the thermal conductivity of a The thermal conductivity of the sample to be measured is measured by the measurement method. The thermal conductivity measurement system includes: a thermal structure, a constant current AC current source, and a lock-in amplifier. The thermal structure includes:

[0051] The substrate 101 is provided with a window 102 .

[0052] The material of the substrate may include but is not limited to silicon.

[0053] As an example, Figure 1 As shown, a top view of a thermal conductivity measurement system is provided, a window 102 is provided on the substrate, and a sample 103 to be measured needs to be mounted on the window 102 of the substrate 101 .

[0054] The sample to be tested 103 has conductive connection ends 104 at both ends thereof, and two detection connection ends 105 are also provided on the sample to be tested, and the two detection connection ends are located between the two conductive connection ends. The sample to be tested is mounted on the window 102 of the substrate 101 through the two conductive connection ends and the two detection connection ends, and is thermally connected to the substrate 101 through the conductive connection ends 104 and the detection connection ends 105.

[0055] The sample to be tested 103 may refer to a sample that needs to be measured for thermal conductivity. In practical applications, the sample to be tested may include but is not limited to CeRhIn5.

[0056] The conductive connection end 104 may refer to electrodes formed at both ends of the sample to be tested after the raw material of the sample to be tested is etched by using a focused ion beam. In practical applications, the conductive connection end may be gold-plated.

[0057] The detection connection end 105 may refer to an electrode formed between the conductive connection ends at both ends of the sample to be tested after the raw material of the sample to be tested is etched by a focused ion beam. In practical applications, the detection connection end may be gold-plated.

[0058] As an example, Figure 2 As shown, a side view of a thermal conductivity measurement system is provided, wherein a conductive connection end 104 is provided at each end of a sample 103 to be tested, and at the same time, two detection connection ends 105 are provided at a portion of the sample 103 to be tested between the two conductive connection ends, and the sample 103 to be tested can be mounted on the window 102 of the substrate 101 through the two conductive connection ends 104 and the two detection connection ends 105.

[0059] The constant current alternating current source is electrically connected to the two conducting connection terminals 104 , and the phase-locked amplifier is electrically connected to the two detecting connection terminals 105 .

[0060] Among them, the constant current AC current source may refer to a power supply that can provide a constant AC current at an output terminal without being affected by changes in load resistance.

[0061] Among them, the phase-locked amplifier can refer to an amplifier used to separate a specific carrier frequency signal from a highly interfering environment (the signal-to-noise ratio can be as low as -60dB or even lower).

[0062] As an example, a constant current AC current source can be used to pass a constant current to the sample 103 to be tested, and a phase-locked amplifier can be used to lock a voltage signal of a selected frequency to measure the voltage of the sample 103 to be tested between the two detection connection terminals 105, and the voltage can include a one-time frequency and a three-time frequency of the voltage. The controller can measure the one-time frequency and the three-time frequency of the voltage as the magnetic field is scanned by changing the temperature and the current, and then the controller can combine the resistance R of the sample to be tested and the rate of change of the resistance of the sample to be tested with the temperature to obtain the one-time frequency and the three-time frequency of the voltage. , and the thermal conductivity calculation expression, the thermal conductivity of the material of the sample 103 to be tested as the magnetic field is scanned is calculated.

[0063] In this embodiment, a constant current alternating current source is used to pass current into the sample to be tested through the two conducting connection ends of the sample to be tested, and a phase-locked amplifier is used to monitor the voltage between the two detection connection ends of the sample to be tested through the two detection connection ends of the sample to be tested. Since the sample to be tested is mounted on the window of the substrate through the two conducting connection ends and the two detection connection ends, the thermal connection only occurs at the detection connection ends and the conducting connection ends of the sample to be tested, and good thermal insulation is maintained. A constant current is passed through the constant current alternating current source to the sample to be tested and the voltage at the selected frequency is monitored by the phase-locked amplifier. The sample to be tested is no longer limited to a macroscopic sample, and the limitation and influence of the sample size on the thermal conductivity measurement can be avoided. By using 3 The measurement method combines current and voltage to accurately calculate the thermal conductivity of the sample to be measured, thereby improving the accuracy of material thermal conductivity measurements.

[0064] In one exemplary embodiment, the material of the sample 103 to be tested may include various conductor materials with different thermal conductivities, such as cerium, rhodium, indium and nickel. The sample to be tested may be used as a subject of electrical measurement to test thermal conductivity. The thermal conductivity measurement system may include a micro-nano electrical structure (such as a thermal structure) and a test electrical element (such as an electrical structure). The thermal structure may be used for thermal connection for heat exchange with the sample, and for electrical connection for signal transmission with the measurement circuit, such as Figure 3As shown, a top view of a thermal structure is provided. The thermal connection of the thermal structure can be completed by direct contact between the substrate 101 and the sample to be tested 103. The heat diffusion area is the four contact areas at both ends of the sample to be tested (such as two conductive connection ends 104 and two detection connection ends 105). In order to maintain good thermal insulation, the substrate under the sample to be tested needs to be hollowed out using a focused ion beam. After the hollowing, a window 102 can be formed on the substrate 101. The sample to be tested 103 is mounted on the window 102, so that the thermal connection only occurs at the four contact areas at both ends of the sample to be tested 103, such as Figure 4 As shown, a side view of a thermal structure is provided, in which the substrate is fixed to the sapphire sheet 106 under the substrate 101 by silver glue.

[0065] In one exemplary embodiment, the system also includes an electrical structure, which includes a first pin 107, a second pin 108, a third pin 109 and a fourth pin 110, the first pin 107 is electrically connected to one of the two conductive connection terminals 104, the second pin 108 is electrically connected to the other of the two conductive connection terminals 104, the third pin 109 is electrically connected to one of the two detection connection terminals 105, and the fourth pin 110 is electrically connected to the other of the two detection connection terminals 105.

[0066] The first pin 107 , the second pin 108 , the third pin 109 and the fourth pin 110 may be gold-plated electrodes.

[0067] As an example, Figure 1As shown, the electrical structure includes a circuit board 111 and a first pin 107, a second pin 108, a third pin 109 and a fourth pin 110 arranged on the circuit board. The shape of the circuit board 111 may include a square. The circuit board 111 may have an 8-pin structure arranged in 2×4. The first pin 107 may be electrically connected to one of the two conductive connection ends 104 through a gold wire and fixed with silver glue. The second pin 108 may be electrically connected to the other of the two conductive connection ends 104 through a gold wire and fixed with silver glue. The third pin 109 may be electrically connected to one of the two detection connection ends 105 through a gold wire and fixed with silver glue. The fourth pin 110 may be electrically connected to the other of the two detection connection ends 105 through a gold wire and fixed with silver glue. It can be understood that the connection method of the first pin 107, the second pin 108, the third pin 109 and the fourth pin 110 to the conductive connection end 104 and the detection connection end 105 can be flexibly adjusted according to actual conditions. In a specific implementation, the number of the first pins 107 may include two. When one of the first pins fails, the remaining first pins can operate normally, thereby confirming that the thermal conductivity measurement system operates normally. The same applies to the second pin 108 , the third pin 109 , and the fourth pin 110 .

[0068] In this embodiment, the pins are electrically connected to the conduction connection terminal and the detection connection terminal respectively, which can provide a basis for the subsequent constant current AC current source to pass a constant current to the sample to be measured, and for the phase-locked amplifier to lock the voltage signal of the selected frequency, thereby ensuring the safe and stable operation of the thermal conductivity measurement system.

[0069] In one exemplary embodiment, one of the two output terminals of the constant-current alternating current source is electrically connected to the first pin 107 , and the other of the two output terminals of the constant-current alternating current source is electrically connected to the second pin 108 .

[0070] As an example, one of the two output terminals of the constant current AC current source is electrically connected to the first pin 107, and the other of the two output terminals of the constant current AC current source is electrically connected to the second pin 108, thereby ensuring that the constant current AC current source can pass a constant current into the sample to be tested.

[0071] In this embodiment, the first pin and the second pin are electrically connected to the output terminal of the constant current AC current source, which can provide a basis for the constant current AC current source to pass a constant current to the sample to be measured, thereby ensuring the safe and stable operation of the thermal conductivity measurement system.

[0072] In one exemplary embodiment, one of the two signal input terminals of the phase-locked amplifier is electrically connected to the third pin 109, the other of the two signal input terminals of the phase-locked amplifier is electrically connected to the fourth pin 110, and the reference signal input terminal of the phase-locked amplifier is electrically connected to the constant current AC current source.

[0073] As an example, one of the two signal input terminals of the phase-locked amplifier is electrically connected to the third pin 109, the other of the two signal input terminals of the phase-locked amplifier is electrically connected to the fourth pin 110, and the reference signal input terminal of the phase-locked amplifier is electrically connected to the constant current AC current source, thereby ensuring that the phase-locked amplifier can lock the voltage signal of the selected frequency.

[0074] In this embodiment, the third pin and the fourth pin are electrically connected to the signal input terminal of the phase-locked amplifier, and the reference signal input terminal of the phase-locked amplifier is electrically connected to the constant current AC current source, which can provide a basis for the phase-locked amplifier to lock the voltage signal of the selected frequency, thereby ensuring the safe and stable operation of the thermal conductivity measurement system.

[0075] In one exemplary embodiment, a sapphire sheet 106 is disposed between the electrical structure and the thermal structure; the sapphire sheet is fixed to the electrical structure and the thermal structure respectively by silver glue.

[0076] The sapphire sheet may be in a square shape.

[0077] As an example, Figure 2 As shown, the thermal structure can be fixed on the sapphire sheet 106 by silver glue; the sapphire sheet 106 can also be connected to the thermal structure by silver glue to provide thermal insulation protection.

[0078] In this embodiment, by providing a sapphire sheet between the electrical structure and the thermal structure, the thermal structure can be insulated and protected, thereby preventing irrelevant factors from affecting the thermal conductivity measurement and improving the accuracy of the thermal conductivity measurement.

[0079] In some embodiments, the present application also provides a method for preparing a thermal structure in the above-mentioned thermal conductivity measurement system, including: fixing a sample material on a substrate using deposited platinum; etching the sample material to form a sample to be tested on the substrate, wherein both ends of the sample to be tested are provided with conductive connection ends, and two detection connection ends are also provided on the sample to be tested, and the two detection connection ends are between the two conductive connection ends; etching the substrate to form a window on the substrate, so that the sample to be tested is mounted on the window of the substrate through the conductive connection ends and the detection connection ends, and is thermally connected to the substrate through the conductive connection ends and the detection connection ends.

[0080] As an example, the preparation method of the thermal structure may include: processing the sample material into a size of 50 microns (to 100 microns) in length, 4 microns (to 20 microns) in width, and 1 micron (to 4 microns) in thickness by a focused ion beam etching method to obtain a pre-processed sample, and transferring the pre-processed sample to a silicon wafer and fixing the pre-processed sample to the silicon wafer using deposited platinum. Subsequently, after evaporating a gold film (with a thickness of 30 nanometers to 200 nanometers) on the surface of the pre-processed sample for treatment, the pre-processed sample is processed into a thin beam structure according to a pre-designed pattern using a focused ion beam etching technique, and four connection ends (such as a conductive connection end and a detection connection end) distributed at both ends of the thin beam are retained for thermal and electrical contact.

[0081] In this embodiment, the sample material is fixed on the substrate by using deposited platinum; the sample material is etched to form a sample to be tested on the substrate, and the two ends of the sample to be tested are provided with conductive connection ends, and the sample to be tested is also provided with two detection connection ends, and the two detection connection ends are between the two conductive connection ends; the substrate is etched to form a window on the substrate, so that the sample to be tested is mounted on the window of the substrate through the conductive connection end and the detection connection end, and is thermally connected to the substrate through the conductive connection end and the detection connection end, which can ensure that the heat diffusion area is the conductive connection end and the detection connection end of the sample, maintain good thermal insulation, and improve the accuracy of thermal conductivity measurement.

[0082] In one exemplary embodiment, the length of the sample to be tested is 50-200 microns, the width is 10-20 microns, and the thickness is 1-4 microns.

[0083] In an exemplary embodiment, Figure 5 As shown, a thermal conductivity measurement method applied to the above thermal conductivity measurement system is provided, and the method is described by taking the application of the method to a terminal as an example, including the following steps S502 to S506. Among them:

[0084] Step S502, obtaining the current between two conductive connection terminals of the sample to be tested.

[0085] As an example, the controller may obtain the current between two conductive connection terminals of the sample to be tested through a constant current alternating current source.

[0086] Step S504, when the temperature of the sample to be tested is 3K, obtain the voltage corresponding to the two detection connection terminals of the sample to be tested, the resistance between the two detection connection terminals of the sample to be tested, and the rate of change of the resistance with temperature.

[0087] As an example, while ensuring that the temperature of the sample to be tested is 3K, the controller can control the magnetic field in the space where the thermal conductivity measurement system is located to perform magnetic field scanning. The controller can obtain the voltage corresponding to the two detection connection terminals of the sample to be tested, the resistance between the two detection connection terminals of the sample to be tested, and the rate of change of resistance with temperature in the process, so as to perform subsequent thermal conductivity calculations.

[0088] Step S506, determining the thermal conductivity of the sample to be tested according to the current, voltage, resistance and change rate.

[0089] As an example, the controller can combine the calculation expression of thermal conductivity, use current, voltage, resistance and change rate to calculate the thermal conductivity of the sample to be tested. In practical applications, the test is completed by passing a constant current through the sample to be tested through a current source to measure the voltage; the voltage is measured by locking the voltage signal of the selected frequency through a phase-locked amplifier, including the first and third times of the voltage; the voltage signal is measured under magnetic field scanning; the first and third times of the voltage as the magnetic field is scanned are measured by changing different temperatures and current sizes, and the resistance R of the sample to be tested and the rate of change of the sample resistance with temperature are combined. ; The continuous thermal conductivity of the material as the magnetic field is scanned can be calculated.

[0090] In the thermal conductivity measurement method, the current between the two conducting connection ends of the sample to be measured is obtained; when the temperature of the sample to be measured is 3K, the voltage corresponding to the two detection connection ends of the sample to be measured, the resistance between the two detection connection ends of the sample to be measured and the rate of change of the resistance with the temperature are obtained; the thermal conductivity of the sample to be measured is determined according to the current, voltage, resistance and rate of change. The thermal conductivity measurement system can be used to measure the thermal conductivity of the sample to be measured, which is not limited to macroscopic samples, and the limitation and influence of the sample size on the thermal conductivity measurement can be avoided. The measurement method combines current and voltage to accurately calculate the thermal conductivity of the sample to be measured, thereby improving the accuracy of material thermal conductivity measurements.

[0091] In an exemplary embodiment, the calculation expression of the thermal conductivity of the sample to be tested is expressed as:

[0092]

[0093] in, is the thermal conductivity, is the current, is the length of the sample to be tested, is the resistance, is the rate of change of resistance, is the triple frequency of the voltage, The voltage corresponding to the two detection connection terminals of the sample to be tested is obtained. is the cross-sectional area of ​​the sample to be tested.

[0094] In one exemplary embodiment, Figure 6 As shown in FIG. 1 , a schematic diagram of the process of measuring thermal conductivity is provided, using an AC current source and a phase-locked amplifier to form a measurement loop with the sample, and using a four-wire method to detect the voltage change of the electrode of the sample to be measured. The entire experiment was conducted in a vacuum chamber at 10 -3 The experimental results were all obtained at 3K.

[0095] In practical applications, the sample to be tested for electrical detection can be designed and cut into the required sample slices using a focused ion beam, with an overall length of 50-200 microns, a width of 10-20 microns, and a thickness of 1-4 microns. The sample is placed on a silicon substrate, with the portion used for measurement suspended and not in contact with the substrate. The sample to be tested is a CeRhIn5 single crystal obtained by vapor deposition. After the sample slice is placed on the substrate, a mask is made on the surface of the sample slice, and the sample is gold-plated. After the gold plating is completed, a focused ion beam is used to cut out the sample thin beam (sample to be tested) needed for measurement in the suspended area of ​​the sample. The length of the sample thin beam is 50 microns, the width is 4 microns, and the thickness is 2 microns. After the focused ion beam cuts the sample thin beam, four electrodes are cut out according to the designed pattern to be used as the detection end and the conduction end, and then they are fixed on the measurement base together with the substrate using silver glue, and the measurement base is used to make good electrical contact with the cut electrodes using silver glue and gold wire. The micro-nano electrical structure is thus prepared. The electrical connection between the thermal and electrical structures consists of platinum deposited on the edge of the sample, a thin film of gold evaporated on the surface of the sample, and a detection circuit formed after segmenting the sample using a focused ion beam.

[0096] In a specific implementation, the thermal conductivity measurement system may also include a rotation mechanism (such as an angle test system), which can control the thermal conductivity measurement system to rotate along a preset axis. When performing a thermal conductivity test on a sample to be tested, the thermal conductivity measurement system may first be transferred to the rotating electrical measuring rod of the rotation mechanism and placed in a vacuum sleeve, and the vacuum degree in the sleeve may be drawn to 10 -3 After the temperature drops below 0.05 Pa, the thermal conductivity measurement system is inserted into a water-cooled magnet to complete a series of calibration and temperature control tasks. In the laboratory coordinate system, a magnetic field is applied in the Z-axis direction, and magnetic fields of 5T, 10T, 15T, 20T, 25T, and 30T are applied respectively. The magnitude of the current I is changed under the corresponding magnetic field, and the voltage V at both ends of the sample under the corresponding current change is recorded. The voltage V can include a voltage one-time frequency signal and a voltage three-time frequency signal V 3ω ,like Figure 7 As shown in FIG. 1 , a schematic diagram of a voltage double frequency signal changing with current is provided, such as Figure 8As shown in FIG. 3 , a schematic diagram of a voltage triple frequency signal changing with current is provided, and a preset current magnitude can be selected as the measured current magnitude. In the measurement method, the electrical signal generated by the sample is related to the current. The sample rod is suspended in the air. The resistance of the sample rod has a strong temperature dependence. Its heat can only be transferred through the measuring electrode. Therefore, when the alternating current is applied to the sample rod, the temperature fluctuation on the surface satisfies the one-dimensional heat conduction equation:

[0097] .

[0098] in, is the density, C p is the specific heat capacity at constant pressure, t is time, T is temperature, T0 is the initial temperature, is the thermal conductivity, x is the spatial coordinate along the direction of heat conduction, I0 is the current, L is the length of the sample, S is the cross-sectional area of ​​the sample, R is the resistance, is the rate of change of resistance with temperature.

[0099] The resistance of the sample surface will fluctuate with temperature. At this time, the frequency of the alternating current is ω. Due to Joule's law, Q=I 2 R, the surface resistance R fluctuation frequency is 2ω. At the same time, according to Ampere's law V=IR, the 3ω in the measured V will contain information about temperature fluctuations, so that information about thermal conductivity can be obtained. Therefore, V can be solved from the one-dimensional heat conduction equation 3ω and thermal conductivity satisfy:

[0100] .

[0101] Among them, I is the input AC current, L is the length of the sample thin beam, and R is the resistance at this temperature, which can be obtained by measurement. is the rate of change of resistance at that temperature, which can be obtained by measuring the resistance at a temperature near the current temperature. is the thermal conductivity of the material, S is the cross-sectional area of ​​the material, which can be obtained from the width and thickness, V 3ω and thermal conductivity The relationship between can be used as a calculation expression for thermal conductivity. For the measurement of resistance R, resistance R is sensitive to temperature. When measuring the change in thermal conductivity of the sample under the change of continuous magnetic field at a temperature of 3K, the measurement of R cannot deviate from its linear region to ensure that the basic temperature of the sample will not shift. For the derivative of resistance For the measurement, select a temperature point near 3K to measure the resistance R. According to the definition of the derivative:

[0102] .

[0103] It can be calculated based on the ratio of the difference between the resistance R(T) of the sample at temperature T and the resistance R(T) of the sample at temperature (T+ΔT) to the time difference ΔT.

[0104] Measure the 3ω response signal V of the sample thin rod at the same temperature 3ω , the thermal conductivity of the material can be solved. When the temperature is 3K, the response of the thermal conductivity of the material to the magnetic field can characterize the change of resistance and thermal conductivity with the magnetic field strength, such as Fig. 9 As shown, a schematic diagram of the change of resistance and thermal conductivity with magnetic field strength is provided. In the specific implementation, the thermal conductivity measurement system has good thermal conductivity; the thermal conductivity measurement system can lock the required frequency in the AC signal with different constant magnitudes input at different temperatures; the thermal conductivity measurement system has the voltage signal response capability under different magnetic fields, and the thermal conductivity measurement system has the ability to complete in-situ rotation under the magnetic field, so that the thermal conductivity values ​​at different angles of magnetic field and heat flow can be obtained.

[0105] In this embodiment, by setting the thermal conductivity measurement system in the magnetic field to be measured, the measured thermal conductivity value is finally calculated according to the voltage and voltage triple frequency signal of the required frequency in the magnetic field scanning read by the phase-locked amplifier, combined with the resistance value of the sample and the change value of the resistance with temperature. The thermal conductivity measurement system can be used to measure the thermal conductivity of the sample to be measured, which is not limited to macroscopic samples, and the limitation and influence of the sample size on the thermal conductivity measurement can be avoided. The measurement method combines current and voltage to accurately calculate the thermal conductivity of the sample to be measured, thereby improving the accuracy of material thermal conductivity measurements.

[0106] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0107] Based on the same inventive concept, the embodiment of the present application also provides a thermal conductivity measuring device for implementing the thermal conductivity measuring method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more thermal conductivity measuring device embodiments provided below can refer to the limitations of the thermal conductivity measuring method above, and will not be repeated here.

[0108] In an exemplary embodiment, Fig.10 As shown, a thermal conductivity measuring device is provided, comprising:

[0109] An acquisition module 1002 is used to acquire the current between two conductive connection terminals of the sample to be tested;

[0110] Monitoring module 1004, used for obtaining, when the temperature of the sample to be tested is 3K, the voltage corresponding to the two detection connection terminals of the sample to be tested, the resistance between the two detection connection terminals of the sample to be tested, and the rate of change of the resistance with temperature;

[0111] The determination module 1006 is used to determine the thermal conductivity of the sample to be tested according to the current, the voltage, the resistance and the change rate.

[0112] In one exemplary embodiment, the thermal conductivity measuring device further includes a calculation module, which is specifically used to determine the calculation expression of the thermal conductivity of the sample to be measured as follows:

[0113]

[0114] in, is the thermal conductivity, is the current, is the length of the sample to be tested, is the resistance, is the rate of change of resistance, is the triple frequency of the voltage, The voltage corresponding to the two detection connection terminals of the sample to be tested is obtained. is the cross-sectional area of ​​the sample to be tested.

[0115] Each module in the above thermal conductivity measuring device can be implemented in whole or in part by software, hardware, or a combination thereof. Each module can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to each module.

[0116] In an exemplary embodiment, a computer device is provided. The computer device may be a terminal, and its internal structure diagram may be as shown in FIG. Fig.11As shown. The computer device includes a processor, a memory, an input / output interface, a communication interface, a display unit and an input device. The processor, the memory and the input / output interface are connected through a system bus, and the communication interface, the display unit and the input device are connected to the system bus through the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the computer device is used to exchange information between the processor and the external device. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be realized through WIFI, a mobile cellular network, near field communication (Near Field Communication, NFC) or other technologies. When the computer program is executed by the processor, a thermal conductivity measurement method is realized. The display unit of the computer device is used to form a visually visible picture, which can be a display screen, a projection device or a virtual reality imaging device. The display screen can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covering the display screen, or a button, trackball or touchpad set on the computer device shell, or an external keyboard, touchpad or mouse.

[0117] Those skilled in the art will understand that Fig.11 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0118] In one embodiment, a computer device is further provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above-mentioned method embodiments when executing the computer program.

[0119] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0120] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0121] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0122] A person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, an artificial intelligence (AI) processor, etc., but are not limited to this.

[0123] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0124] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the present application. It should be noted that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A thermal conductivity measurement system, characterized in that: The thermal conductivity measurement system is used to adopt 3 The thermal conductivity of the sample to be measured is measured by the measuring method. The system comprises: a thermal structure, a constant current alternating current source, and a phase-locked amplifier. The thermal structure comprises: A substrate, wherein the substrate is provided with a window; A sample to be tested, wherein two ends of the sample to be tested are provided with conductive connection ends, and the sample to be tested is also provided with two detection connection ends, wherein the two detection connection ends are located between the two conductive connection ends, and the sample to be tested is mounted on the window of the substrate through the conductive connection ends and the detection connection ends, and is thermally connected to the substrate through the conductive connection ends and the detection connection ends; the sample to be tested is a conductive material; The constant current alternating current source is electrically connected to the two conducting connection terminals, and the phase-locked amplifier is electrically connected to the two detecting connection terminals.

2. The system according to claim 1, characterized in that The system also includes an electrical structure, which includes a first pin, a second pin, a third pin and a fourth pin, the first pin is electrically connected to one of the two conductive connection ends, the second pin is electrically connected to the other of the two conductive connection ends, the third pin is electrically connected to one of the two detection connection ends, and the fourth pin is electrically connected to the other of the two detection connection ends.

3. The system according to claim 2, characterized in that One of the two output terminals of the constant-current alternating current source is electrically connected to the first pin, and the other of the two output terminals of the constant-current alternating current source is electrically connected to the second pin.

4. The system according to claim 2, characterized in that One of the two signal input terminals of the phase-locked amplifier is electrically connected to the third pin, the other of the two signal input terminals of the phase-locked amplifier is electrically connected to the fourth pin, and the reference signal input terminal of the phase-locked amplifier is electrically connected to the constant current AC current source.

5. The system according to claim 2, characterized in that A sapphire sheet is arranged between the electrical structure and the thermal structure.

6. The system according to claim 5, characterized in that The sapphire sheet is fixed to the electrical structure and the thermal structure respectively through silver glue.

7. A method for preparing a thermal structure in a thermal conductivity measurement system according to any one of claims 1 to 6, characterized in that: The method comprises: The sample material was fixed to the substrate using deposited platinum; Etching the sample material to form a sample to be tested on the substrate, wherein two ends of the sample to be tested are provided with conductive connection ends, and the sample to be tested is also provided with two detection connection ends, and the two detection connection ends are located between the two conductive connection ends; The substrate is etched to form a window on the substrate, so that the sample to be tested is mounted on the window of the substrate through the conductive connection end and the detection connection end, and is thermally connected to the substrate through the conductive connection end and the detection connection end.

8. The method according to claim 7, characterized in that The sample to be tested has a length of 50-200 microns, a width of 10-20 microns, and a thickness of 1-4 microns.

9. A method for measuring thermal conductivity using the thermal conductivity measurement system according to any one of claims 1 to 6, characterized in that: The method comprises: Obtaining the current between two conductive connection terminals of the sample to be tested; When the temperature of the sample to be tested is 3K, obtaining the voltage corresponding to the two detection connection terminals of the sample to be tested, the resistance between the two detection connection terminals of the sample to be tested, and the rate of change of the resistance with temperature; The thermal conductivity of the sample to be tested is determined according to the current, the voltage, the resistance and the rate of change.

10. The method according to claim 9, characterized in that The calculation expression of the thermal conductivity of the sample to be tested is expressed as: in, is the thermal conductivity, is the current, is the length of the sample to be tested, is the resistance, is the rate of change of resistance, is the triple frequency of the voltage, The voltage corresponding to the two detection connection terminals of the sample to be tested is obtained. is the cross-sectional area of ​​the sample to be tested.

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