Temperature sensor, temperature detection device, and temperature detection method

Abstract

To provide a new temperature sensor structure that utilizes the Seebeck effect. [Solution] A temperature sensor having an electrically conductive conductor capable of generating a thermoelectric voltage due to a temperature difference, wherein the conductor has broken time-reversal symmetry and spatial inversion symmetry.

Description

Technical Field

[0001] The present disclosure relates to a temperature sensor, a temperature detection device, and a temperature detection method.

Background Art

[0002] With the progress of industrial automation through factory automation, the expansion of the healthcare field for visualizing physical conditions, the development of the automotive industry due to temperature management of batteries with the spread of electric vehicles and hybrid vehicles, and the increasing demand for household electrical appliances such as smart home appliances and wearable devices, the temperature sensor is expected to grow in the future market.

[0003] Among temperature sensors, thermocouples are widely used in various fields including industrial applications because of their fast response speed and high durability. This thermocouple measures temperature based on the Seebeck effect, in which two different metal materials are joined and a voltage is generated when a temperature difference occurs at the joint.

[0004] As temperature sensors using thermocouples, improving the deviation of the measured temperature by the drift phenomenon (for example, Patent Document 1), durability, and providing a coating layer on the thermoelectron strands to improve environmental resistance (for example, Patent Document 2) have been studied.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] An object of the present disclosure is to provide a temperature sensor with a new structure using the Seebeck effect. [Means for solving the problem]

[0007] The present inventors have discovered that in a conductor exhibiting electrical conductivity and having broken time-reversal symmetry and spatial inversion symmetry, a thermoelectric voltage based on the Seebeck effect is generated in a direction intersecting the temperature difference within the conductor, and that by measuring this thermoelectric voltage, it is possible to detect the temperature difference, thus completing the present invention. Accordingly, the embodiments of this disclosure are as follows.

[0008] [1] A temperature sensor having an electrically conductive conductor capable of generating a thermoelectric voltage due to a temperature difference, wherein the conductor has broken time-reversal symmetry and spatial inversion symmetry.

[0009] [2] The temperature sensor according to [1], wherein the conductor is capable of generating an effective Seebeck coefficient that is greater than the Seebeck coefficient of the conductor.

[0010] [3] The temperature sensor according to [2], wherein the effective Seebeck coefficient is generated by supplying current to the conductor.

[0011] [4] A temperature sensor according to any one of [1] to [3], having a voltage output terminal that outputs a voltage of the thermoelectric power generated in the conductor.

[0012] [5] The temperature sensor according to any one of [1] to [4], wherein the conductor is a bonded substrate having a PN junction or a spin junction.

[0013] [6] The temperature sensor according to any one of [1] to [5], wherein the conductor comprises a chiral metal, a polar metal, or a magnetic metal.

[0014] A temperature detection device comprising a temperature sensor described in any one of [1] to [6], wherein the temperature detector comprises a voltage detection unit and a temperature difference detection unit, the voltage detection unit detects the voltage of the thermoelectric power generated in the conductor of the temperature sensor, and the temperature difference detection unit detects the temperature difference of the conductor of the temperature sensor based on the voltage detection result.

[0015] [8] The temperature detection device according to [7], wherein the temperature difference detection unit detects the temperature difference of the conductor of the temperature sensor based on the voltage detection result and the Seebeck coefficient of the conductor of the temperature sensor.

[0016] [9] The temperature detector further includes a current supply unit that supplies current in a direction intersecting the temperature difference of the conductor of the temperature sensor, and the temperature difference detection unit detects the temperature difference of the conductor of the temperature sensor based on the voltage detection result and the effective Seebeck coefficient generated by supplying current to the conductor of the temperature sensor. The temperature detection device according to [7].

[0017]

[10] The current supply unit supplies alternating current, the temperature detection device according to [9].

[0018]

[11] The temperature detection device according to [7], wherein the temperature difference detection unit detects the temperature difference of the conductor of the temperature sensor by quantitatively evaluating the voltage detection result.

[0019] A temperature detection method comprising: a contact step of bringing a temperature sensor described in any one of [1] to [6] into contact with an object to be temperature detected; a voltage detection step of detecting the voltage of the thermoelectric power generated in the conductor of the temperature sensor; and a temperature difference detection step of detecting the temperature difference of the conductor of the temperature sensor based on the voltage detection result.

[0020]

[13] The temperature detection method according to

[12] , wherein the temperature difference detection step detects the temperature difference of the conductor of the temperature sensor based on the voltage detection result and the Seebeck coefficient of the conductor of the temperature sensor.

[0021]

[14] The temperature detection method according to

[12] , wherein the temperature difference detection step is performed while supplying a current in a direction intersecting the temperature difference of the conductor of the temperature sensor, and the temperature difference detection step detects the temperature difference of the conductor of the temperature sensor based on the voltage detection result and the effective Seebeck coefficient generated by supplying a current to the conductor of the temperature sensor.

[0022]

[15] The temperature detection method according to

[12] , wherein the temperature difference detection step is to detect the temperature difference of the conductor of the temperature sensor by quantitatively evaluating the voltage detection result. [Effects of the Invention]

[0023] This disclosure makes it possible to provide a new temperature sensor structure that utilizes the Seebeck effect. By using this temperature sensor, it is possible to provide a new temperature detection device and temperature detection method. [Brief explanation of the drawing]

[0024] [Figure 1A] This is a plan view showing an example of a temperature sensor according to one embodiment of the present disclosure. [Figure 1B] Figure 1A is a front view of the temperature sensor. [Figure 2] This figure illustrates another example of a temperature sensor according to one embodiment of the present disclosure, where (a) is a perspective view showing the configuration of the temperature sensor, and (b) is a conceptual diagram showing the relationship between the external magnetic field B, the heat flow jQ, and the electric field E. [Figure 3] This is a block diagram showing the configuration of a temperature detection device according to one embodiment of the present disclosure. [Figure 4] This flowchart shows an example of the flow of the voltage detection process in a temperature detection method according to one embodiment of this disclosure. [Figure 5] This is a phase diagram of the amorphous MoGe film prepared in Example 1. [Figure 6A] This graph shows the relationship between the external magnetic field B and the cross-nonlinear voltage VCross 3ω when a predetermined AC current IMoGe is supplied to the amorphous MoGe film of the temperature sensor fabricated in Example 1. [Figure 6B] Figure 6A is a graph showing the relationship between the alternating current IMoGe and the peak amplitude ACross 3ω of the cross-nonlinear voltage VCross 3ω. [Figure 7A] This graph shows the relationship between the external magnetic field B and the cross-nonlinear voltage VCross 3ω when a predetermined heater current IH is input to the heater of the temperature sensor fabricated in Example 1. [Figure 7B] Figure 7A is a graph showing the relationship between the alternating current IH and the peak amplitude ACross 3ω of the cross-nonlinear voltage VCross 3ω. [Modes for carrying out the invention]

[0025] The embodiments for implementing this disclosure will be described in detail below with reference to the attached drawings. In each drawing, the same reference numerals are used for the same elements where possible. In addition, the dimensional ratios within and between components in the drawings are arbitrary for the sake of readability.

[0026] [Temperature sensor] Figure 1A is a plan view showing an example of a temperature sensor according to one embodiment of the present invention. Figure 1B is a side view of the temperature sensor shown in Figure 1A.

[0027] In Figures 1A and 1B, the sensor 1 includes a thermoelectric conversion unit 10, a voltage output terminal 20, and a temperature control unit 30. For the sake of explanation, the thermoelectric conversion unit 10 is shown as a rectangular parallelepiped, but it does not have to be a rectangular parallelepiped. Hereafter, in a plan view, the direction of the longer side may be called the x-direction, and the direction of the shorter side may be called the Y-direction. Also, the direction perpendicular to the x-direction and the Y-direction may be called the thickness direction or z-direction.

[0028] One side of the thermoelectric conversion unit 10 in the thickness direction (the bottom side in Figure 1B) is a heat receiving surface 10s that contacts the object to be temperature detected 2 and receives heat from the object to be temperature detected 2. The heat receiving surface 10s is at the same temperature as the object to be temperature detected 2. The object to be temperature detected 2 may be a solid, a liquid, or a gas. The side of the thermoelectric conversion unit 10 opposite to the object to be temperature detected 2 is a temperature reference surface 10t. For the sake of explanation, the temperature reference surface 10t is adjusted to a different temperature from the object to be temperature detected 2, but it may simply be a heat dissipation surface. When the heat receiving surface 10s and the temperature reference surface 10t of the thermoelectric conversion unit 10 are at different temperatures, a temperature difference (temperature gradient) is created, and heat flow j Q A voltage output terminal 20 is located on a pair of surfaces along the short side of the thermoelectric conversion unit 10. A temperature adjustment unit 30 is located on the temperature reference surface 10t.

[0029] The thermoelectric conversion unit 10 is an electrically conductive conductor that exhibits broken time-reversal symmetry and broken spatial inversion symmetry. The thermoelectric conversion unit 10 may exhibit broken time-reversal symmetry and broken spatial inversion symmetry upon application of an external magnetic field B, or it may exhibit broken time-reversal symmetry and broken spatial inversion symmetry even without the application of an external magnetic field B. As the material for the thermoelectric conversion unit 10, for example, chiral metals, polar metals, or magnetic metals can be used. The thermoelectric conversion unit 10 may be a single entity consisting only of a conductor with broken time-reversal symmetry and broken spatial inversion symmetry, or it may be a laminate having a thermoelectric conversion layer made of a conductor with broken time-reversal symmetry and broken spatial inversion symmetry. The laminate may be a junction substrate having, for example, a PN junction or a spin junction.

[0030] The voltage output terminal 20 outputs a voltage of the thermoelectric voltage V generated in the thermoelectric conversion unit 10. For example, the material of the voltage output terminal 20 can be metallic materials such as Cu, Ag, Au, Pt, Ni, Al, constantan, Cr, In, Pd, Fe, Cu alloys, Ti / Au laminates, and Cr / Au laminates, as well as conductive oxides such as indium tin oxide (ITO) and zinc oxide (ZnO).

[0031] The temperature adjustment unit 30 adjusts the temperature of the temperature reference surface 10t of the thermoelectric conversion unit 10. By adjusting the temperature of the temperature reference surface 10t of the thermoelectric conversion unit 10 in the temperature adjustment unit 30, the heat flow j is generated due to the temperature difference between the heat receiving surface 10s and the temperature reference surface 10t. Q This is generated. A heater, cooler, or heat sink can be used as the temperature control unit 30. Alternatively, a thermometer may be placed to measure the temperature of the temperature reference surface 10t of the thermoelectric conversion unit 10 instead of the temperature control unit 30.

[0032] In the temperature sensor 1, when a temperature difference occurs between the heat receiving surface 10s and the temperature reference surface 10t, a thermoelectric voltage V is generated inside the thermoelectric conversion unit 10 due to the Seebeck effect. Since the thermoelectric conversion unit 10 has broken time-reversal symmetry and spatial inversion symmetry, the thermoelectric voltage V is generated in a direction intersecting the temperature difference, i.e., the heat flow j Q It is generated in a direction intersecting the direction (the +z direction in Figure 1A). When the thermoelectric conversion unit 10 exhibits breaking of time-reversal symmetry and spatial inversion symmetry due to the application of an external magnetic field B, the thermoelectric voltage V is generated by the heat flow j Q It is generated in a direction that intersects with the direction of the magnetic field (+z direction) and also intersects with the direction in which the external magnetic field B is applied (+y direction).

[0033] The thermoelectric power V(V) generated in the thermoelectric conversion unit 10 is expressed by the following equation (1).

[0034] V = S × △T (1)

[0035] In equation (1), S is the Seebeck coefficient (V / K), and ΔT is the temperature difference (K), representing the difference (Tt-Ts) between the temperature Ts of the heat-receiving surface 10s and the temperature Tt of the temperature reference surface 10t.

[0036] The temperature of the object to be detected (temperature of the heat-receiving surface 10s) can be determined, for example, as follows: Measure the thermoelectric power V from the voltage output terminal 20. Then, using the obtained thermoelectric power V and the Seebeck coefficient S of the thermoelectric conversion unit 10 at the temperature of the temperature reference surface 10t, calculate the temperature difference ΔT. Then, using the temperature difference ΔT and the temperature of the temperature reference surface 10t, calculate the temperature of the heat-receiving surface 10s.

[0037] To improve the accuracy of the temperature of the heat receiving surface 10s, the thermoelectric conversion unit 10 may be capable of generating an effective Seebeck coefficient S' that is larger than the Seebeck coefficient S of the thermoelectric conversion unit 10. The effective Seebeck coefficient S' can be generated, for example, by supplying a current in a direction (+x direction) that intersects the temperature difference of the thermoelectric conversion unit 10.

[0038] The effective Seebeck coefficient S'(V / K) when current is supplied to the thermoelectric conversion unit 10 is expressed, for example, by the following equation (2).

[0039] S' = S0 + S1 × I (2)

[0040] In equation (2), S0 is the basic Seebeck coefficient (V / K), which represents the Seebeck coefficient of the thermoelectric conversion unit 10 when no current is supplied; S1 is the current sensitivity constant of the Seebeck coefficient (V / K·A), which represents the amount of change in the Seebeck coefficient of the thermoelectric conversion unit 10 caused by supplying current; and I is the amount of current (A), which represents the amount of current supplied to the thermoelectric conversion unit 10.

[0041] When current is supplied to the thermoelectric conversion unit 10, the thermoelectric electromotive force V generated in the thermoelectric conversion unit 10 is expressed by the following equation (3). The thermoelectric electromotive force V expressed by the following equation (3) is a nonlinear voltage that changes with respect to the current I and the temperature difference ΔT.

[0042] V=S'△T=S0△T+(S1×I)△T (3)

[0043] If the temperature of the heat-receiving surface 10s is Ts and the temperature of the temperature reference surface 10t is Tt, then the temperature Ts(K) of the heat-receiving surface 10s can be calculated using the following equation (4).

[0044] Ts = Tt - V / (S0 + S1 × I) (4)

[0045] The basic Seebeck coefficient S0 and the current sensitivity S1 of the Seebeck coefficient can be obtained, for example, by the following method. A predetermined temperature is applied to the heat receiving surface 10s and the temperature reference surface 10t of the thermoelectric conversion unit 10 to generate a predetermined temperature difference ΔT. Next, the thermoelectric electromotive force V generated in the thermoelectric conversion unit 10 is measured while supplying current to the thermoelectric conversion unit 10. A graph is created with the horizontal axis as the amount of current I supplied to the thermoelectric conversion unit 10 and the vertical axis as V / ΔT, which is the thermoelectric electromotive force V divided by the temperature difference ΔT. The slope of the IV / ΔT line in the obtained graph is taken as the current sensitivity S1 of the Seebeck coefficient, and V / ΔT when I=0 is taken as the basic Seebeck coefficient S0.

[0046] Next, a modified example of a temperature sensor will be described, using a temperature sensor in which the thermoelectric conversion unit 10 is a bonded substrate having a spin junction as an example.

[0047] Figure 2 illustrates another example of a temperature sensor according to one embodiment of the present disclosure, where (a) is a perspective view showing the configuration of the temperature sensor, and (b) shows the external magnetic field B and heat flow j Q This is a conceptual diagram showing the relationship between the temperature and the electric field E. The temperature sensor 1a shown in Figure 2 has a thermoelectric conversion section 10a which has a laminated structure in which a substrate 11, a magnetic insulating layer 12, and a superconducting material layer 13 are stacked in that order.

[0048] The substrate 11 is a substantially plate-shaped member that holds the magnetic insulating layer 12 and the superconducting material layer 13, with a magnetic insulating layer 12 and a superconducting material layer 13 formed on one surface. The material of the substrate 11 is not limited, but a material capable of forming the magnetic insulating layer 12 is selected. In Figure 2, the substrate 11 is Gd3Ga5O oriented on the (111) plane. 12 An example using (GGG) is shown. The thickness of the substrate 11 may be, for example, 500 μm.

[0049] The magnetic insulating layer 12 is a layer made of an electrically insulating magnetic material, formed on the substrate 11 with a superconducting material layer 13 formed on its upper surface. The material of the magnetic insulating layer 12 is not limited, but a material that can be formed on the substrate 11 is selected. In Figure 2, Y3Fe5O is used as the magnetic insulating layer 12. 12An example using (YIG) is shown. On a substrate 11 made of GGG, a magnetic insulating layer 12 made of YIG can be grown using a conventionally known liquid phase epitaxial growth method. The thickness of the magnetic insulating layer 12 may be, for example, 3 μm. Here, the magnetic insulating layer 12 is provided only on one surface side of the superconducting material layer 13, and has a structure that breaks the spatial symmetry when viewed from the superconducting material layer 13.

[0050] The superconducting material layer 13 is a layer made of a superconducting material formed on the upper surface of the magnetic insulating layer 12. The material of the superconducting material layer 13 is not limited, but a material that can be formed on the magnetic insulating layer 12 is selected. In FIG. 2, an example using a film of amorphous MoGe, which is a type-II superconductor, as the superconducting material layer 13 is shown. As shown in (b), in the superconducting state of the type-II superconductor, vortices 13a, which are quantized magnetic fluxes, are generated. When an external magnetic field B is applied, the vortices 13a are oriented along the direction of application of the external magnetic field B (+y direction) and enter a vortex liquid state. The movement of the vortices 13a along the heat flux j Q causes an electric field E to be generated in the direction (+x direction) that intersects the direction of the heat flux j Q and also intersects the direction of application of the external magnetic field B (+y direction), and a voltage is generated. At this time, the spatial inversion symmetry of the superconducting material layer 13 is broken due to the presence of the magnetic insulating layer. Due to this breaking of the spatial inversion symmetry, when a current I is supplied in the direction (+x direction) in which the electric field E is generated in addition to the heat flux j Q , the value of the electric field E derived from the heat flux j Q changes due to the current I.

[0051] The superconducting material layer 13 made of an amorphous MoGe film can be formed on the magnetic insulating layer 12 using a conventionally known high-frequency sputtering method. The thickness of the superconducting material layer 13 may be, for example, 150 nm. Also, as conditions for the high-frequency sputtering method of MoGe, for example, while water-cooling the substrate 11, an Ar pressure of 2.8×10 -1 Pa, a growth rate of 5 nm / min, a rotation speed of the substrate 11 of 3000 rpm, etc. can be mentioned.

[0052] The thermoelectric conversion unit 10a is obtained by growing a magnetic insulating layer 12 on a substrate 11 using a liquid-phase epitaxial method, forming a superconducting material layer 13 on the magnetic insulating layer 12 using a high-frequency sputtering method, and then dicing it to an element size of, for example, 6.6 mm × 2 mm.

[0053] In this example, a resistance heating heater 30a is positioned on the surface of the superconducting material layer 13 opposite to the substrate 11, via an insulating material 25, to generate a temperature difference. The resistance heating heater 30a has a pair of electrodes 31 and a thin-film resistor 32 positioned between the pair of electrodes 31. The resistance heating heater 30a generates Joule heat when an electric current is supplied between the pair of electrodes 31. The electrodes 31 of the resistance heating heater 30a are connected to a temperature gradient generating unit 130, which will be described later. As the material for the insulating material 25, for example, resin, rubber, or ceramic can be used.

[0054] A pair of voltage output terminals (not shown) are located on the short-side surfaces of the superconducting material layer 13. These voltage output terminals are connected to a potential difference measuring unit 140, which will be described later.

[0055] In the temperature sensor 1a shown in Figure 2, the temperature of the surface of the superconducting material layer 13 opposite to the substrate 11 is adjusted by a resistance heater 30a. Therefore, the surface of the superconducting material layer 13 opposite to the substrate 11 can be used as a temperature reference surface 13t. The surface of the superconducting material layer 13 on the substrate 11 side can be used as a heat receiving surface 13s that receives heat from the substrate 11 via the magnetic insulating layer 12 to the object to be detected. The position of the resistance heater 30a should be such that the temperature of the temperature reference surface 13t of the superconducting material layer 13 can be adjusted. For example, the resistance heater 30a may be arranged so as to sandwich the temperature reference surface 13t of the superconducting material layer 13. Alternatively, the resistance heater 30a may be placed on the substrate 11, and the surface of the superconducting material layer 13 on the substrate 11 side may be used as the temperature reference surface 13t, and the surface opposite to the substrate 11 side may be used as the heat receiving surface 13s.

[0056] [Temperature detection device] Figure 3 is a block diagram showing the configuration of a temperature detection device according to one embodiment of the present disclosure.

[0057] In Figure 3, the temperature detection device 100 includes a temperature sensor 1a and a temperature detector (voltage detection unit 110, temperature difference detection unit 180). The voltage detection unit 110 is the part that detects the voltage of the thermoelectric voltage generated in the thermoelectric conversion unit 10a of the temperature sensor 1a. The voltage detection unit 110 includes a magnetic field application unit 120, a temperature gradient generation unit 130, a potential difference measurement unit 140, a lock-in detection unit 150, a phase change measurement unit 160, and an intensity calculation unit 170. The temperature difference detection unit 180 is the part that detects the temperature difference of the thermoelectric conversion unit 10a of the temperature sensor 1a based on the voltage detection result.

[0058] The temperature detection device 100 is realized by controlling the voltage detection unit 110 and the temperature difference detection unit 180 hardware with a computer. The computer is a device that processes various information according to predetermined procedures and is equipped with a central processing unit (CPU), memory, external storage device, and various interfaces. The computer is also connected to the hardware shown in Figure 3 via various interfaces, enabling information communication, and controls the operation by sending control signals and acquiring various information from the hardware.

[0059] The magnetic field application unit 120 is the part that applies an external magnetic field B to the superconducting material layer 13 of the temperature sensor 1a. The specific configuration of the magnetic field application unit 120 is not limited, but as the source of the external magnetic field B, for example, an electromagnet or a permanent magnet can be used. An electromagnet is preferred because the direction and strength of the magnetic field can be easily controlled. Here, the magnetic field application unit 120 is used to facilitate voltage measurement by applying an external magnetic field B to the thermoelectric conversion unit 10a of the temperature sensor 1a. If the temperature sensor 1a does not require an external magnetic field B to generate voltage, the magnetic field application unit 120 may be omitted.

[0060] The temperature gradient generation unit 130 is the part that generates a temperature gradient in the superconducting material layer 13 of the temperature sensor 1a in order to experimentally generate a temperature difference. The specific configuration of the temperature gradient generation unit 130 is not limited, but for example, it may include a heater power supply (not shown) that supplies current to the resistance heating heater 30a of the temperature sensor 1a. The temperature gradient generation unit 130 may change the temperature difference of the superconducting material layer 13 over time by controlling the current supplied from the heater power supply to the resistance heating heater 30a, thereby generating a temperature gradient between both sides of the superconducting material layer 13. The current supplied from the temperature gradient generation unit 130 to the resistance heating heater 30a may have a superposition of DC and AC components.

[0061] The potential difference measuring unit 140 is the part that measures the potential difference generated in the superconducting material layer 13 of the temperature sensor 1a. The configuration of the potential difference measuring unit 140 is not limited, but one example is the heat flow j generated by the temperature gradient. Q One possible configuration involves forming two voltage output terminals on opposing sides of the thermoelectric conversion unit 10a in a direction intersecting the direction of the external magnetic field B application, and measuring the potential difference between the voltage output terminals with a voltmeter.

[0062] The lock-in detection unit 150 is a part that detects predetermined frequency components from fluctuations over time with respect to the potential difference measured by the potential difference measurement unit 140 in order to improve detection sensitivity. The specific configuration of the lock-in detection unit 150 is not limited, and conventionally known lock-in amplifiers can be used. The lock-in detection unit 150 has a current supply unit that supplies an alternating current of a predetermined frequency to the superconducting material layer 13 in a direction intersecting the temperature difference generated by the temperature gradient generation unit 130.

[0063] The phase change measurement unit 160 is the part that introduces a phase difference into the AC component of the current supplied to the resistance heating heater 30a of the temperature sensor 1a. By changing the phase difference Φ of the AC component applied to the resistance heating heater 30a and measuring the predetermined frequency component of the potential difference generated at the thermoelectric conversion unit 10a of the temperature sensor 1a with the potential difference measurement unit 140, the potential distribution at the phase difference Φ can be obtained.

[0064] The intensity calculation unit 170 is the part that calculates the nonlinear thermoelectric intensity β based on the distribution of predetermined frequency components acquired by the phase change measurement unit 160.

[0065] The temperature difference detection unit 180 extracts a voltage perpendicular to the temperature difference at a predetermined frequency component from the nonlinear thermoelectric intensity β. Using the extracted voltage as the thermoelectric power V, the temperature difference ΔT between the temperature Ts of the heat receiving surface 13s of the superconducting material layer 13 of the temperature sensor 1a and the temperature Tt of the temperature reference surface 13t is calculated. The temperature difference ΔT can be calculated based on the above equation (3). The temperature Ts of the heat receiving surface 13s of the superconducting material layer 13 can be calculated using the above equation (4).

[0066] [Temperature detection method] A temperature detection method according to one embodiment of this disclosure will be described using the above-described temperature detection device 100 as an example. The temperature detection method of this embodiment includes a contact step, a voltage detection step, and a temperature difference detection step.

[0067] The contact process involves bringing the thermoelectric conversion unit 10a of the temperature sensor 1a into contact with the object whose temperature is to be detected. Through this contact process, the substrate 11 of the thermoelectric conversion unit 10a comes into contact with the object whose temperature is to be detected, and the temperature of the object is transferred to the heat receiving surface 13s of the superconducting material layer 13 of the thermoelectric conversion unit 10a. In this example, a resistance heating heater 30a is used as the object whose temperature is to be detected in order to experimentally generate a temperature difference.

[0068] The voltage detection process involves detecting the voltage of the thermoelectric voltage generated in the thermoelectric conversion unit 10a of the temperature sensor 1a. Figure 4 is a flowchart showing an example of the flow of the voltage detection process.

[0069] The voltage detection process, as shown in Figure 4 for example, involves generating a temperature gradient and inputting current S1, applying a magnetic field S2, measuring a potential difference S3, detecting lock-in S4, measuring a phase change S5, and calculating the intensity S6.

[0070] In the temperature gradient generation / current input S1, to improve detection sensitivity, a current with a superimposed DC component and AC component (for example, an AC component with frequency 2ω) is supplied to the resistance heating heater 30a of the temperature sensor 1a while changing the phase difference Φ, thereby generating Joule heat in the resistance heating heater 30a, and using this Joule heat to heat the temperature reference surface 13t of the superconducting material layer 13. This generates a temperature gradient (temperature difference) between the heat receiving surface 13s (the surface on the substrate 11 side) and the temperature reference surface 13t (the surface on the resistance heating heater 30a side) of the superconducting material layer 13. Then, in order to improve detection sensitivity, an AC current (for example, an AC current with frequency 5ω) is supplied in a direction intersecting the temperature difference of the superconducting material layer 13. The temperature gradient is generated by the temperature gradient generation unit 130. Voltage detection is performed by the lock-in detection unit 150.

[0071] In magnetic field application S2, an external magnetic field B is applied to the superconducting material layer 13 of the temperature sensor 1a. The magnetic field is applied by the magnetic field application unit 120.

[0072] In the potential difference measurement S3, the potential is measured in a direction that intersects the direction of the heat flow jQ generated by the temperature gradient of the superconducting material layer 13 and the direction of application of the external magnetic field B. The potential is measured by the potential difference measurement unit 140.

[0073] In lock-in detection S4, a predetermined frequency component is detected using the time-dependent fluctuation of the potential difference measured in potential difference measurement S3. Lock-in detection is performed by the lock-in detection unit 150.

[0074] In phase change measurement S5, a phase difference Φ is introduced into the AC component of the current supplied to the resistance heating heater 30a, and the potential is measured in a direction that intersects the direction of the heat flow jQ generated by the temperature gradient of the superconducting material layer 13 and the direction of application of the external magnetic field B. From the measurement result of the potential difference, the potential distribution with respect to the phase difference Φ is obtained by lock-in detection of a specific frequency component. The phase change measurement is performed by the temperature gradient generation unit 130, the potential difference measurement unit 140, the lock-in detection unit 150, and the phase change measurement unit 160.

[0075] The intensity calculation S6 calculates the nonlinear thermoelectric intensity β based on the distribution of predetermined frequency components obtained by the phase change measurement unit 160 obtained in the phase change measurement S5. The intensity calculation is performed by the intensity calculation unit 170.

[0076] The temperature difference detection step detects the temperature difference of the superconducting material layer 13 based on the voltage detection result obtained in the voltage detection step. Specifically, a nonlinear voltage (cross-nonlinear voltage) perpendicular to the temperature difference is extracted from the nonlinear thermoelectric intensity β obtained in intensity calculation S6 at a predetermined frequency component, and the temperature difference ΔT between the temperature Ts of the heat-receiving surface of the superconducting material layer 13 and the temperature Tt of the temperature reference surface is calculated using the extracted cross-nonlinear voltage as the thermoelectric voltage V. The temperature difference ΔT can be calculated based on the above equation (3). The temperature Ts of the heat-receiving surface of the superconducting material layer 13 can be calculated using the above equation (4). The temperature difference detection step is performed by the temperature difference detection unit 180.

[0077] Although embodiments of the present disclosure have been described above, the present disclosure is not limited to the embodiments described above. For example, the resistance heating heater 30a is provided merely to experimentally generate a temperature difference. Furthermore, in order to improve the detection sensitivity, the temperature detection device 100 of this embodiment is provided with a lock-in detection unit 150 and supplies an alternating current of a predetermined frequency to the superconducting material layer 13 in a direction intersecting the temperature difference, but the configuration of the temperature detection device 100 is not limited to this.

[0078] The temperature detection device 100 may be configured to detect the temperature difference ΔT based on equation (1) using the thermoelectric power V and the Seebeck coefficient S. In this case, it is not necessary to supply current in a direction intersecting the temperature difference.

[0079] The temperature detection device 100 may be configured to detect the temperature difference ΔT by quantitatively evaluating the thermoelectric power V. Specifically, a relationship between the thermoelectric power V and the temperature difference ΔT may be prepared in advance, and the temperature difference ΔT may be calculated by substituting the measured thermoelectric power V into this relationship.

[0080] In the temperature detection method of this embodiment, in the temperature gradient generation and current input S1 of the voltage detection step, a current is supplied in a direction intersecting the temperature difference, and in the temperature difference detection step, the temperature difference ΔT is detected based on equation (3) using the thermoelectric power V and the effective Seebeck coefficient S'. However, the method for calculating the temperature difference ΔT by the temperature detection method is not limited to this.

[0081] For example, the temperature difference ΔT may be detected based on equation (1) using the thermoelectric power V and the Seebeck coefficient S. In this case, it is not necessary to supply current in a direction intersecting the temperature difference.

[0082] The temperature difference ΔT may be detected by quantitatively evaluating the thermoelectric power V. Specifically, a relationship between the thermoelectric power V and the temperature difference ΔT may be prepared in advance, and the temperature difference ΔT may be calculated by substituting the measured thermoelectric power V into this relationship. The thermoelectric power V does not need to be quantitatively evaluated. For example, the temperature difference ΔT can be calculated based on the current I at which the thermoelectric power V reaches a predetermined value. Alternatively, the temperature difference ΔT may be measured using only the effective Seebeck coefficient S' by applying an alternating current I of frequency ω and detecting the alternating current of frequency ω.

[0083] Embodiments of this disclosure are described below.

[0084] [Note 1] A temperature sensor having an electrically conductive conductor capable of generating a thermoelectric voltage due to a temperature difference, wherein the conductor has broken time-reversal symmetry and spatial inversion symmetry. According to the temperature sensor described in Appendix 1, since the time-reversal symmetry and spatial inversion symmetry of the conductor are broken, the thermoelectric voltage can be generated in a direction different from the temperature difference, making it easier to extract the thermoelectric voltage to the outside. For this reason, there is no need to join two types of metal materials, making it easier to miniaturize and increase sensitivity compared to conventional thermocouples.

[0085] [Note 2] The temperature sensor described in Appendix 1 generates the thermoelectric power in a direction intersecting the temperature difference. According to the temperature sensor in Appendix 2, since the thermoelectric power is generated in a direction intersecting the temperature difference, it is easier to extract the thermoelectric power externally. For this reason, it is easier to miniaturize compared to conventional thermocouples.

[0086] [Note 3] The conductor is capable of generating an effective Seebeck coefficient greater than the Seebeck coefficient of the conductor, as described in Appendix 1 or 2. According to the temperature sensor in Appendix 3, the voltage of the thermoelectric force generated in the direction intersecting the temperature difference becomes larger, thus increasing sensitivity.

[0087] [Note 4] The effective Seebeck coefficient is generated by supplying current to the conductor, as described in Appendix 3 of the temperature sensor. According to the temperature sensor in Appendix 4, the effective Seebeck coefficient can be reliably generated, thus ensuring higher sensitivity.

[0088] [Note 5] A temperature sensor as described in any one of the appendices 1 to 4, having a voltage output terminal that outputs the voltage of the thermoelectric voltage generated in the aforementioned conductor. According to the temperature sensor described in appendice 5, it is easier to extract the voltage of the thermoelectric voltage generated in the direction intersecting the temperature difference to the outside.

[0089] [Note 6] The conductor has two or more surfaces aligned with the direction in which the thermoelectric power is generated, and one of these surfaces is a heat-receiving surface that receives heat from the object whose temperature is to be detected, as described in any one of Appendices 1 to 5. According to the temperature sensor of Appendice 6, a thermoelectric power can be generated by the temperature difference of the conductor caused by the heat-receiving surface receiving heat, so the temperature of the object whose temperature is to be detected can be measured with high sensitivity.

[0090] [Note 7] The temperature sensor described in Appendix 6, wherein the surface of the conductor facing the heat-receiving surface is a temperature reference surface adjusted to a temperature different from the temperature of the object to be detected. According to the temperature sensor described in Appendix 7, a temperature difference based on the object to be detected can be reliably generated, so the temperature of the object to be detected can be measured with greater accuracy.

[0091] [Note 8] The temperature sensor according to any one of the appendices 1 to 7, wherein the conductor is a bonded substrate having a PN junction or a spin junction. According to the temperature sensor of appendice 8, the conductor is prone to breaking time-reversal symmetry and spatial inversion symmetry.

[0092] [Note 9] The temperature sensor according to any one of the appendices 1 to 8, wherein the conductor includes a chiral metal, a polar metal, or a magnetic metal. According to the temperature sensor of appendice 9, the conductor is prone to breaking time-reversal symmetry and spatial inversion symmetry.

[0093] [Note 10] A temperature sensor having an electrically conductive conductor and a heat-receiving surface that receives heat from an object to be detected, wherein the conductor has broken time-reversal symmetry and spatial inversion symmetry. According to the temperature sensor of Appendix 10, because the time-reversal symmetry and spatial inversion symmetry of the conductor are broken, it is possible to generate a thermoelectric voltage in a direction intersecting the temperature difference caused by the heat-receiving surface receiving heat, and the temperature of the object to be detected can be detected from the voltage of that thermoelectric voltage. For this reason, there is no need to join two types of metal materials, and it is easier to miniaturize compared to conventional thermocouples, and the sensitivity is higher.

[0094] [Note 11] The temperature sensor described in Appendix 10, wherein the surface of the conductor facing the heat receiving surface is a temperature reference surface adjusted to a temperature different from the temperature of the object to be detected. According to the temperature sensor described in Appendix 11, a temperature difference based on the object to be detected can be reliably generated, so the temperature of the object to be detected can be measured with greater accuracy.

[0095] [Note 12] A temperature detection device comprising a temperature sensor described in any one of appendices 1 to 11 and a temperature detector, wherein the temperature detector comprises a voltage detection unit and a temperature difference detection unit, the voltage detection unit detects the voltage of the thermoelectric voltage generated in the conductor of the temperature sensor, and the temperature difference detection unit detects the temperature difference of the conductor of the temperature sensor based on the voltage detection result. According to the temperature detection device of appendice 12, the temperature difference can be detected with high sensitivity based on the voltage of the thermoelectric voltage generated in the temperature sensor.

[0096] [Note 13] The temperature detection device described in Appendix 12 detects the temperature difference of the conductor of the temperature sensor based on the voltage detection result and the Seebeck coefficient of the conductor of the temperature sensor. According to the temperature detection device described in Appendix 13, the temperature difference is detected based on the voltage of the thermoelectric power generated by the temperature sensor and the Seebeck coefficient of the conductor, so the temperature difference can be detected with greater accuracy.

[0097] [Note 14] The temperature detector further includes a current supply unit that supplies current in a direction intersecting the temperature difference of the conductor of the temperature sensor, and the temperature difference detection unit detects the temperature difference of the conductor of the temperature sensor based on the voltage detection result and the effective Seebeck coefficient generated by supplying current to the conductor of the temperature sensor, as described in Appendix 12. According to the temperature detection device of Appendix 14, the temperature difference is detected based on the voltage of the thermoelectric force generated by the temperature sensor and the effective Seebeck coefficient of the conductor, so the temperature difference can be detected with high accuracy even when the Seebeck coefficient of the conductor is small.

[0098] [Note 15] The current supply unit is a temperature detection device as described in Appendix 14 that supplies alternating current. According to the temperature detection device as described in Appendix 15, lock-in detection technology can be used, so the temperature difference can be detected with even greater accuracy.

[0099] [Note 16] The temperature detection device described in Appendix 12 detects the temperature difference of the conductor of the temperature sensor by quantitatively evaluating the voltage detection result. According to the temperature detection device described in Appendix 16, the temperature difference can be detected directly based on the detected thermoelectric voltage, so the temperature difference can be detected easily and accurately.

[0100] [Note 17] A temperature detection method comprising: a contact step of bringing a temperature sensor described in any one of appendices 1 to 11 into contact with an object to be temperature detected; a voltage detection step of detecting the voltage of the thermoelectric power generated in the conductor of the temperature sensor; and a temperature difference detection step of detecting the temperature difference of the conductor of the temperature sensor based on the voltage detection result. According to the temperature detection method of appendice 17, the temperature difference can be detected with high sensitivity based on the voltage of the thermoelectric power generated by the temperature sensor.

[0101] [Note 18] The temperature detection step is the temperature detection method described in Appendix 17, which detects the temperature difference of the conductor of the temperature sensor based on the voltage detection result and the Seebeck coefficient of the conductor of the temperature sensor. According to the temperature detection method described in Appendix 18, the temperature difference is detected based on the voltage of the thermoelectric power generated by the temperature sensor and the Seebeck coefficient of the conductor, so the temperature difference can be detected with greater accuracy.

[0102] [Note 19] The temperature detection method according to Appendix 17, wherein the temperature difference detection step is performed while supplying a current in a direction intersecting the temperature difference of the conductor of the temperature sensor, and the temperature difference detection step detects the temperature difference of the conductor of the temperature sensor based on the voltage detection result and the effective Seebeck coefficient generated by supplying a current to the conductor of the temperature sensor. According to the temperature detection method of Appendix 19, the temperature difference is detected based on the voltage of the thermoelectric force generated in the temperature sensor and the effective Seebeck coefficient of the conductor, so the temperature difference can be detected with high accuracy even when the Seebeck coefficient of the conductor is small.

[0103] [Note 20] The temperature detection method described in Appendix 19, wherein the current supplied in a direction intersecting the temperature difference of the conductor is an alternating current. According to the temperature detection method described in Appendix 20, since lock-in detection technology can be used, the temperature difference can be detected with even greater accuracy.

[0104] [Note 21] The temperature detection step is the temperature detection method described in Appendix 17, which detects the temperature difference of the conductor of the temperature sensor by quantitatively evaluating the voltage detection result. According to the temperature detection method described in Appendix 21, the temperature difference can be detected directly based on the detected thermoelectric voltage, so the temperature difference can be detected easily and accurately. [Examples]

[0105] Next, to clarify the effects of this disclosure, examples will be used. However, this disclosure is not limited to these examples.

[0106] (Fabrication of a temperature sensor) Gd3Ga5O oriented on the (111) plane 12 (GGG) A 1 μm thick layer of Y3Fe5O is placed on the top surface of a substrate (thickness: 500 μm). 12 A (YIG) film was grown by liquid-phase epitaxy. Next, the resulting laminate was diced so that its long side was 6.6 mm and its short side was 2.0 mm. Then, an amorphous MoGe film with a thickness of 150 nm was deposited on the upper surface of the YIG film by sputtering. In this way, a laminate consisting of a GGG substrate, a YIG film, and an amorphous MoGe film stacked in this order was obtained, and a thermoelectric conversion unit was fabricated.

[0107] Electrodes were formed on each of the opposing short-side planes of the amorphous MoGe film obtained in the thermoelectric conversion section.

[0108] Next, a resistance heating heater was placed on the upper surface of the amorphous MoGe film of the obtained thermoelectric conversion section, with an insulating material in between. In this way, a temperature sensor with the configuration shown in Figure 2 was fabricated.

[0109] Here, we will describe the amorphous MoGe film prepared in Example 1. Figure 5 is a phase diagram of the amorphous MoGe film prepared in Example 1. In Figure 5, B c2 and B m These represent the upper critical magnetic field and the vortex solid melting magnetic field, respectively. In the central region of the horizontal axis, where the absolute value of the external magnetic field B is small, the external magnetic field B is smaller than the critical magnetic field, indicating that the resistance of the amorphous MoGe film is zero and that it is in a superconducting state. The intermediate region between the superconducting and normal conducting states is near the phase transition magnetic field where the resistance of the amorphous MoGe film changes rapidly. In the superconducting state, quantized magnetic flux (vortex) is pinned in the amorphous MoGe film, but near the phase transition temperature, the pinning of the quantized magnetic flux is released, resulting in a vortex liquid phase where vortexes move freely within the amorphous MoGe film. The vortex liquid phase in this phase diagram exhibits low symmetry in time reversal and low symmetry in space reversal. For example, at a temperature of 4.5 K, the vortex liquid phase state is achieved with a magnetic field application of around ±2 T.

[0110] (Evaluation of temperature sensors) A temperature sensor was placed in an environment with a temperature of 4.5K. The thermoelectric power (cross-nonlinear voltage) of the temperature sensor was measured, which was generated by the temperature difference between the temperature of the amorphous MoGe film (superconducting material layer 13), heated by Joule heating from a heater (resistance heating heater 30a) placed on the upper surface of the amorphous MoGe film (superconducting material layer 13), and the ambient temperature.

[0111] To detect the generation of thermoelectric power with high sensitivity, a lock-in technique was used. Specifically, an alternating current was input between electrodes formed on an amorphous MoGe film (superconducting material layer 13), and the alternating current (I=I) was applied in a direction intersecting the temperature difference of the amorphous MoGe film (the +x direction in Figure 2). MoGe A magnetic field of sin(5ωt)I was supplied. An external magnetic field B was supplied in the short-side direction (+y direction in Figure 2) of the amorphous MoGe film (see Figure 2).

[0112] The heater (resistance heating heater 30a) has a current (heater current) of I HWhen an alternating current sinωt is input, Joule heat (∝I H sinωt) 2 A mixture was generated, and an AC temperature difference (ΔT∝cos2ωt) was applied in the thickness direction (+z direction in Figure 2) of the amorphous MoGe film (superconducting material layer 13).

[0113] Cross-nonlinear voltage (V) generated in the longitudinal direction (+x direction in Figure 2) of the amorphous MoGe film (superconducting material layer 13) Cross The coefficient I × ΔT) oscillates in time at the angular frequencies of the sum of the frequencies of the AC current and the AC temperature difference ΔT (5ω + 2ω) and their difference (5ω - 2ω) (i.e., 7ω and 3ω). To eliminate the influence of the multiplication of the AC current input to the amorphous MoGe film and the harmonic response to the AC temperature difference ΔT, a low angular frequency of 3ω was selected for lock-in detection, and the 3ω lock-in voltage V3ω generated in the amorphous MoGe film (superconducting material layer 13) along the +x direction under an external magnetic field B in the +y direction was measured.

[0114] Figure 6A shows the amorphous MoGe film of the temperature sensor receiving a predetermined AC current I MoGe When the external magnetic field B and the crossover nonlinear voltage V are input, Cross 3ω This graph shows the relationship with a predetermined AC current I. MoGe These values ​​are 20 μA (a), 40 μA (b), 60 μA (c), 80 μA (d), and 100 μA (e). Note that the heater current I input to the heater is... H The current was fixed at 3.5mA. Figure 6B shows the AC current I MoGe and crossing nonlinear voltage V Cross 3ω Peak amplitude A Cross 3ω This graph shows the relationship with V. From the graph in Figure 6A, V Cross 3ω The peak is peak amplitude A Cross 3ω all I MoGe Appears in the value, |A Cross 3ω The value of | is I MoGe It can be seen that it increases with increasing . Also, from the graph in Figure 6B, VCross 3ω Peak amplitude A Cross 3ω AC current I MoGe When plotted as a function of A, 3ω The value of I MoGe It can be seen that it is proportional to [the given value].

[0115] Figure 7A shows a predetermined heater current I applied to the heater of the temperature sensor. H When the external magnetic field B and the crossover nonlinear voltage V are input, Cross 3ω This graph shows the relationship with a predetermined heater current I. H These values ​​are 1.6mA(f), 2.2mA(g), 2.7mA(h), 3.1mA(i), and 3.5mA(j). Note that the AC current I input to the amorphous MoGe film is... MoG The current was fixed at 100 μA. Figure 7B shows the heater current I H and crossing nonlinear voltage V Cross 3ω Peak amplitude A Cross 3ω This graph shows the relationship with V. From the graph in Figure 7A, V Cross 3ω The peak is peak amplitude A Cross 3ω All heater currents I H Appears in the value, |A Cross 3ω The value of | is I H It can be seen that it increases with increasing . Also, from the graph in Figure 7B, V Cross 3ω Peak amplitude A Cross 3ω AC current I MoGe When plotted as a function of A, 3ω The value of heater current I H It can be seen that it is proportional to the square of [the given value].

[0116] The results shown in Figures 6A and 6B and Figures 7A and 7B represent the observed cross-nonlinear voltage V. Cross 3ω Peak amplitude A Cross 3ωThis refers to the amount of alternating current I input to the amorphous MoGe film in the thermoelectric conversion film portion of the temperature sensor. MoGe and heater current I H This shows that it is proportional to [the temperature difference]. This suggests that the effective value of the Seebeck coefficient can be controlled by supplying a current in a direction intersecting the temperature difference of the amorphous MoGe film. Furthermore, by controlling the effective Seebeck coefficient, it becomes possible to obtain a higher degree of precision in the temperature difference of the amorphous MoGe film.

[0117] In this embodiment, a superconducting spin junction was described as an example of a conductor exhibiting time-reversal low symmetry and spatial-reversal low symmetry, as well as electrical conductivity. However, spin junctions or pn junctions that do not use superconducting materials may also be used. Furthermore, chiral metals, polar metals, magnetic metals, etc., may also be used. Various modifications are possible within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Explanation of Symbols]

[0118] 1, 1a…Temperature sensor, 2…Temperature detection target, 10, 10a…Thermoelectric conversion unit, 10s, 13s…Heat receiving surface, 10t, 13t…Temperature reference surface, 11…Voltage detection unit, 12…Magnetic insulating layer, 13…Superconducting material layer, 13a…Vortex filament, 20…Voltage output terminal, 25…Insulating material, 30…Temperature adjustment unit, 30a…Resistance heating type heater, 31…Electrode, 32…Thin film resistor, 100…Temperature detection device, 110…Voltage detection unit, 120…Magnetic field application unit, 130…Temperature gradient generation unit, 140…Potential difference measurement unit, 150…Lock-in detection unit, 160…Phase change measurement unit, 170…Intensity calculation unit, 180…Temperature difference detection unit

Claims

1. A temperature sensor having an electrically conductive conductor and capable of generating thermoelectric power due to a temperature difference, The conductor is a temperature sensor in which time-reversal symmetry and spatial inversion symmetry are broken.

2. The temperature sensor according to claim 1, wherein the conductor is capable of generating an effective Seebeck coefficient that is greater than the Seebeck coefficient of the conductor.

3. The temperature sensor according to claim 2, wherein the effective Seebeck coefficient is generated by supplying current to the conductor.

4. The temperature sensor according to claim 1 or 2, having a voltage output terminal that outputs a voltage of the thermoelectric power generated in the conductor.

5. The temperature sensor according to claim 1 or 2, wherein the conductor is a bonded substrate having a PN junction or a spin junction.

6. The temperature sensor according to claim 1 or 2, wherein the conductor includes a chiral metal, a polar metal, or a magnetic metal.

7. The temperature sensor and temperature detector are as described in claim 1 or 2. The temperature detector has a voltage detection unit and a temperature difference detection unit. The voltage detection unit detects the voltage of the thermoelectric power generated in the conductor of the temperature sensor. The temperature difference detection unit is a temperature detection device that detects the temperature difference of the conductor of the temperature sensor based on the voltage detection result.

8. The temperature detection device according to claim 7, wherein the temperature difference detection unit detects the temperature difference of the conductor of the temperature sensor based on the voltage detection result and the Seebeck coefficient of the conductor of the temperature sensor.

9. The temperature detector further includes a current supply unit that supplies current in a direction intersecting the temperature difference of the conductor of the temperature sensor. The temperature detection device according to claim 7, wherein the temperature difference detection unit detects the temperature difference of the conductor of the temperature sensor based on the voltage detection result and the effective Seebeck coefficient generated by supplying current to the conductor of the temperature sensor.

10. The current supply unit supplies alternating current, as described in claim 9.

11. The temperature detection device according to claim 7, wherein the temperature difference detection unit detects the temperature difference of the conductor of the temperature sensor by quantitatively evaluating the voltage detection result.

12. A contact step of bringing the temperature sensor according to claim 1 or 2 into contact with an object whose temperature is to be detected, A voltage detection step for detecting the voltage of the thermoelectric power generated in the conductor of the temperature sensor, A temperature detection method comprising: a temperature difference detection step of detecting the temperature difference of the conductor of the temperature sensor based on the voltage detection result.

13. The temperature detection method according to claim 12, wherein the temperature difference detection step detects the temperature difference of the conductor of the temperature sensor based on the voltage detection result and the Seebeck coefficient of the conductor of the temperature sensor.

14. The temperature difference detection step is performed while supplying current in a direction intersecting the temperature difference of the conductor of the temperature sensor. The temperature detection method according to claim 12, wherein the temperature difference detection step detects the temperature difference of the conductor of the temperature sensor based on the voltage detection result and the effective Seebeck coefficient generated by supplying current to the conductor of the temperature sensor.

15. The temperature detection method according to claim 12, wherein the temperature difference detection step detects the temperature difference of the conductor of the temperature sensor by quantitatively evaluating the voltage detection result.

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