JPH0129247B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a thermometer for measuring extremely low temperatures, and more specifically, it uses an amorphous alloy that transitions to a superconducting state near absolute zero and measures its electrical resistance. It detects low temperature. Cryogenic thermometers commonly used in the past are
This is a resistance thermometer that uses a Ge semiconductor element to indirectly detect temperature by measuring its electrical resistance using the four-terminal method.This Ge semiconductor element is sealed in a capsule with helium gas. Because of this, it has a low thermal conductivity, making it difficult to measure temperature accurately.Also, because the thermal conductivity is low, it is necessary to embed it in the location to be measured. Furthermore, because the wiring inside the capsule uses very thin lead wires to prevent heat from entering, it can break even at the slightest excessive current and is extremely susceptible to mechanical shock. It was hot. The present invention is intended to solve the above-mentioned drawbacks, and is intended to (1) improve measurement accuracy, (2) simplify the mechanism, and (3) improve strength in temperature measurement.
One or more types of amorphous alloys that transition to superconductivity at a specific temperature within the range of 11〓 are installed at the location to be measured as an electrical resistance element, and the electrical resistance is measured by electrodes and lead wires provided on the element. It measures the value. When the measured point reaches the superconducting transition temperature, the electrical resistance of the element becomes 0, and by detecting this change, the temperature of the measured point can be accurately detected. As a result of various studies on the amorphous alloy,
Za-Mb-(Q+Al)c superconducting alloy is optimal. However, in the formula, Z is any one or more of Zr, Hf, and Ti, and is a atomic %, M is one or more of V, Nb, and Ta, and is b atomic %, and Q is Si,
Consisting of one or both of Ge, Q and Al
Indicates that the total content of c atomic % is contained, and a is 10 to
90, b is 80 or less, c is in the range of 10 to 25, Q is 2 atomic % or more, Al is 0.1 to 15 atomic %, and a + b
+c is substantially 100 and is an alloy containing an amorphous alloy of 20% or more by volume, (Q+Al) with the above composition
Alloys containing an amorphous alloy with a volume fraction of 20% or more in which a part of is replaced with 12 atomic % or less of C, B, or Sn, and crystallized alloys with a volume ratio of 20% or less Indicates an alloy containing 20% or more of an amorphous alloy in terms of volume fraction, which has been heat-treated in a temperature range above this temperature. Regarding this alloy, patent application No. 57-049910 filed by the present inventors dated March 26, 1982,
The detailed description is given in Tables 1 to 3 of the specification of the invention titled "Ultra-quenched superconducting alloy". Said Za―Mb―
The alloy obtained by rapidly solidifying (Q+Al)c alloy from its molten state has a Tc in the range of 4 to 11, high normal conductivity resistance, small superconducting transition width,
and exhibits excellent tape formability, high strength and toughness. In addition, a MoSi-based or MoC-based alloy produced by a sputtering method can be used as the element of the cryogenic thermometer of the present invention. For example, Mo ₇₂ Si ₂₈ alloy is 7.63K, Mo ₆₀ Si ₄₀ is 5.58K, Mo ₇₈ C ₂₂ is 6.97K,
Mo ₆₂ C ₃₈ has a Tc of 7.77K. Next, regarding the cryogenic thermometer using the above-mentioned amorphous alloy, (1) Since it can be measured by directly contacting the member to be measured, heat transfer is large and accurate measurement is possible. (2) There is no need to embed it in the solid part to be measured, eliminating the need for drilling and filling techniques. (3) Compared to semiconductor devices, there is no need to use thin lead wires, no precision is required for current control, and it is resistant to mechanical shock. (4) There is very little variation in the characteristics of each element made of an amorphous alloy, and a calibration table is unnecessary. (5) This is an extremely low cost thermometer for cryogenic temperatures. Examples based on the present invention will be described below. After melting the Za-Mb-(Q+Al)c-based alloy in an Ar gas atmosphere using a levitation furnace, the molten metal is passed through a quartz tube nozzle hole with an inner diameter of about 0.5 mm and a tube with a diameter of about 200 mm rotating at about 4000 rpm. A ribbon-shaped sample with a width of about 1 mm and a thickness of about 20 μm was prepared by supplying it hanging onto the surface of a copper roll and rapidly solidifying it.
Using the four-probe method, we calculated the superconducting transition temperature (Tc), its transition width (△Tc), and the normal conductivity resistance (ρn).
was measured. The results are shown in Table 1.

[Table] Next, a one-point detection type thermometer will be explained with reference to Figures 1 and 2. 1 is a part of the cryogenic member of the object to be measured, 2 is an amorphous superconducting alloy,
3 is an epoxy adhesive, 4 is a low-temperature solder, 5 is a filler, 6a and 6b are copper lead wires (diameter approx.
0.2mm), and Figure 2 shows the electrical resistance of this example.
Shows a graph of temperature. The superconducting alloy in this case is No.1Zr ₈₀ Nb ₅ Al ₆ Si ₉ shown in Table 1, and the electrical resistance value transitions to 0 at 4.21〓. An embodiment of a multi-point detection type is shown in FIGS. 3 and 4. 11 is a part of the cryogenic member of the object to be measured;
2 is an amorphous superconducting alloy, 12a is Zr ₈₀ Nb ₅ Al ₆ Si ₉ shown in No. 1 in Table 1, and 12b is Zr _82.5 Nb _2.5 shown in No. 4.
Al ₈ Si ₇ , 12c is No. 2 Zr ₈₀ Nb ₅ Al ₈ Si ₇ , 12d
is No. 3 Zr ₈₀ Nb ₅ Al ₉ Si ₆ . 13 is epoxy adhesive, 14 is low temperature solder, 15 is filler, 1
6a and 16b are copper lead wires (diameter approximately 0.2
mm), 17 is a polyimide resin. Note 12a,
Elements 12b, 12c, and 12d are connected in series with low-temperature solder 14, and are attached to the member to be measured 11 with adhesive 13. Figure 4 shows the shape of the amorphous superconducting alloy with a width of 1.0 mm in the multi-point detection thermometer shown in Figure 3.
This is a graph showing the relationship between electrical resistance and temperature when the length is 5.0 mm, the length is 5.0 mm, and the thickness is 0.03 mm. The value below is 0, and the extremely low temperature within this range can be accurately detected. As described above, the present invention measures the temperature of a material to be measured using one or more kinds of amorphous alloys that transition to superconductivity at an absolute temperature of 4 to 11 as a plate of electrically resistive material. The present invention provides a cryogenic thermometer that is simple and extremely reliable.

[Brief explanation of drawings]

In FIG. 1, A is a schematic diagram of a single-point detection type thermometer according to the present invention, B is an enlarged cross-sectional view, and FIG. 2 is a graph showing the relationship between temperature and electrical resistance. Figure 3 A is a schematic diagram of a multi-point detection thermometer based on the present invention, B and A are cross-sectional views taken from A to A, and C is an enlarged view of the bonded part between the amorphous metal and the lead wire. It is a diagram. FIG. 4 is a graph showing the relationship between temperature and electrical resistance of a multi-point detection thermometer. 1, 11... Member to be measured, 2, 12a to 12d
...Amorphous superconducting alloy.

Claims (1)

[Claims] 1 Za transfers to superconductivity at absolute temperature of 4° to 11゜
Mb-(Q+Al)c-based superconducting alloy, where Z
is one or more of Zr, Hf, and Ti.
Atomic %, M is any one or two of V, Nb, and Ta
Species or more are b atomic %, Q consists of one or both of Si and Ge, and the total of Q and Al is c atomic %
Indicates that it contains, a is 10 to 90, b is 80 or less,
c is in the range of 10 to 25, Q is 2 atomic % or more, Al is 0.1
~15 atomic %, a + b + c is substantially 100, and an alloy containing this superconducting alloy in a volume fraction of 20% or more, and furthermore, a part of (Q + Al) of the above composition is replaced with either C, B, or Sn. Alloys containing 12 atomic % or less of one or more types substituted with a volume fraction of 20% or more, and alloys containing 20% or more of a volume fraction of the above alloys that have been heat-treated at a temperature of 1273 or less and above the crystallization temperature. A cryogenic thermometer that measures temperature by forming an alloy into a plate shape or a thin film shape, adhering one or more kinds of them to an object to be measured as an electrical resistance material, and measuring the electrical resistance.