JP2013201114A - Intermediate layer having substrate for superconducting thin film wire material and superconducting thin film wire material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for obtaining, by means of a MOD method, an oxide superconducting wire material which does not degrade in Jc even when a calcination film is laminated and which is excellent in superconducting characteristics (having high Jc and high Ic).SOLUTION: An intermediate layer having substrate is used for a production of a superconducting thin film wire material by a coating thermal decomposition method. In the intermediate layer having substrate for the superconducting thin film wire material, an intermediate layer is provided on an oriented metal substrate, and the intermediate layer having a four-layer structure in which a CeOlayer, a YSZ layer, a YOlayer, a CeOlayer are arranged in this order from a surface toward the oriented metal substrate. The oriented metal substrate is a clad substrate in the intermediate layer having substrate for the superconducting thin film wire material. An oxide superconducting layer is formed on the intermediate layer having substrate for the superconducting thin film wire material by a coating thermal decomposition method in a superconducting thin film wire material.

Description

  The present invention relates to a substrate with an intermediate layer used when producing a superconducting thin film wire by a coating pyrolysis method and a superconducting thin film wire produced by a coating pyrolysis method using the substrate with an intermediate layer.

  Since the discovery of high-temperature superconductors that have superconductivity at the temperature of liquid nitrogen, development of high-temperature superconducting wires aimed at application to power devices such as cables, current limiters, and magnets has been actively conducted. Among these, a superconducting thin film wire in which an oxide superconducting layer is formed on a substrate has attracted attention.

One method for producing such an oxide superconducting wire is a so-called coating pyrolysis method (Metal Organic Deposition, abbreviated as MOD method) (Patent Document 1). In the MOD method, a raw material solution (MOD solution) produced by dissolving each organic metal compound of RE (rare earth element), Ba (barium) and Cu (copper) in a solvent is applied to an oriented metal substrate to form a coating film. After the formation, for example, a calcining heat treatment is performed at around 500 ° C. to thermally decompose the organometallic compound to produce a calcined film that is a precursor of the oxide superconductor. A method of manufacturing an oxide superconducting wire by forming a REBCO-based oxide superconducting layer represented by REBa ₂ Cu ₃ O _7-X by performing crystallization by performing a main annealing heat treatment at around 750 to 800 ° C. Compared to vapor phase methods (evaporation method, sputtering method, pulsed laser deposition method, etc.) that are mainly manufactured in a vacuum, it is easy to reduce the cost of manufacturing equipment, and it can handle large areas and complex shapes. With features such as easy Order, are widely used.

  Then, the oxide superconducting thin film layer is laminated by repeating the application of the MOD solution, the calcination heat treatment, and the main baking heat treatment, thereby increasing the thickness of the oxide superconducting thin film layer to the superconducting characteristics (critical current density Jc and critical current value). Ic and the like) are being improved.

JP 2007-165153 A

  However, there is a problem that even if the main film is laminated and thickened by the MOD method as described above, Jc is lowered and Ic is not sufficiently extended. For this reason, there is a demand for a technique capable of obtaining an oxide superconducting wire excellent in superconducting characteristics (having high Jc and Ic) by using the MOD method without Jc being lowered even when the fired film is laminated. .

  The present inventor has intensively studied to solve the above-mentioned problems, and the cause of the decrease in Jc due to the increase in the thickness of the oxide superconducting thin film layer lies in the repetition of the main annealing heat treatment performed when the main sintering film is laminated. By changing the structure of the intermediate layer formed on the metal substrate, Jc does not decrease even when the main-fired heat treatment is repeated to laminate the main-fired film, and an oxide superconducting wire excellent in superconducting characteristics can be obtained. I found out that I can do it.

That is, in the case of the conventional MOD method, the intermediate layer is usually provided on the oriented metal substrate as shown in FIG. FIG. 3 is a diagram schematically showing a conventional substrate 3 with an intermediate layer in which an intermediate layer 31 is provided on an oriented metal substrate 11. The intermediate layer 31 is a ceramic layer provided for growing a c-axis oriented oxide superconductor crystal on the oriented metal substrate 11 to form an oxide superconducting layer, and generally using an RF sputtering method. A Y ₂ O ₃ layer or a CeO ₂ layer as a seed layer (seed film layer) 31 a for forming a c-axis oriented ceramic layer on the oriented metal substrate 11, a metal element contained in the oriented metal substrate 11 As a YSZ layer as a barrier layer (diffusion prevention layer) 31b for preventing diffusion, and as a cap layer (lattice matching layer) 31c for matching the lattice constant of the metal constituting the oriented metal substrate 11 and the oxide superconductor The intermediate layer 3 having a three-layer structure formed in the order of the _two CeO layers is used.

However, the Y ₂ O ₃ layer and the CeO ₂ layer that are the seed layer 31a have the following characteristics. That is, since the Y ₂ O ₃ layer has a high oxygen diffusion suppressing function with respect to the oriented metal substrate, oxidation of the outermost surface of the oriented metal substrate in the subsequent process can be suppressed, while the crystal orientation on the oriented metal substrate is reduced. Not enough. On the contrary, the CeO ₂ layer has good crystal orientation of the oxide superconductor on the oriented metal substrate, but has high oxygen permeability, so that the outermost surface of the oriented metal substrate is oxidized in the subsequent step.

As described above, the Y ₂ O ₃ layer and the CeO ₂ layer are seed layers having advantages and disadvantages. However, in the case of the conventional MOD method that does not perform the lamination of the fired film, these disadvantages become a problem. There was almost no. However, if the main-fired film is to be laminated by repeating the main heat treatment, the main heat-treatment is repeated and exposed to a high temperature of about 800 ° C. for a long time in an oxygen atmosphere. Adverse effects began to appear.

That is, when the seed layer 31a is a Y ₂ O ₃ layer, since the crystal orientation is low, the crystal orientation of the epitaxially grown oxide superconducting layer is also low, and high Jc cannot be obtained.

On the other hand, when the seed layer 31a is a CeO ₂ layer, a large amount of oxygen is diffused on the oriented metal substrate and the surface of the oriented metal substrate is oxidized, leading to a rise in grain boundaries and an increase in roughness, resulting in superconducting characteristics. It will cause a decline.

Therefore, the present inventor considered that the seed layer is composed of two layers in order to supplement each defect in the Y ₂ O ₃ layer and the CeO ₂ layer with the other advantage instead of the conventional one layer. Various experiments were conducted. As a _result, the simply stacking the Y 2 _{O 3} layer and CeO ₂ layer, but it is impossible to obtain excellent _{superconductivity,} upon lamination of the Y 2 _{O 3} layer and CeO ₂ layer, identifies an order of lamination Thus, it was found that an oxide superconducting wire having excellent superconducting characteristics can be obtained.

That is, when a CeO ₂ layer is provided on an oriented metal substrate and a Y ₂ O ₃ layer is provided on the CeO ₂ layer, the first CeO ₂ layer allows the crystal orientation of the oriented metal substrate to be sufficiently changed to a CeO ₂ layer. As a result, the second Y ₂ O ₃ layer can sufficiently suppress oxygen diffusion into the oriented metal substrate. Since the Y ₂ O ₃ layer and the CeO ₂ layer are ceramic layers, the crystal orientation of the CeO ₂ layer is not lowered and is inherited by the Y ₂ O ₃ layer. As a result, the seed layer can fully exhibit the low oxygen permeability, good crystal orientation, and two characteristics, and Jc does not decrease even if the main-fired heat treatment is repeated to stack and increase the thickness of the main-fired film. I understood that.

On the other hand, when the Y ₂ O ₃ layer is provided on the oriented metal substrate and the CeO ₂ layer is provided thereon, the first Y ₂ O ₃ layer has sufficient crystal orientation of the oriented metal substrate. It was found that the decrease in Jc cannot be suppressed because it cannot be taken over.

The present invention is based on the above findings, and the invention according to claim 1
A substrate with an intermediate layer used when producing a superconducting thin film wire by a coating pyrolysis method,
An intermediate layer is provided on the oriented metal substrate,
A superconducting thin film characterized in that the intermediate layer has a four-layer structure of a CeO ₂ layer, a YSZ layer, a Y ₂ O ₃ layer, and a CeO ₂ layer in order from the surface side to the oriented metal substrate side. It is a board | substrate with an intermediate | middle layer for wires.

  As described above, the intermediate layer having the four-layer structure described above does not stack the fired film because the seed layer can sufficiently exhibit the low oxygen permeability, good crystal orientation, and two characteristics. Also, the effect is sufficiently exerted in the formation of the single-layered fired film.

The invention described in claim 2
2. The substrate with an intermediate layer for a superconducting thin film wire according to claim 1, wherein the oriented metal substrate is a clad substrate.

  Among the above-mentioned oriented metal substrates, the clad substrate is preferable because the surface thereof is crystal-oriented and has sufficient mechanical strength and is flexible when made long. And as a clad substrate, the Ni-Cu-SUS clad substrate which is excellent in surface orientation and mechanical strength is preferable.

The invention according to claim 3
3. The substrate with an intermediate layer for a superconducting thin film wire according to claim 1, wherein the CeO ₂ layer on the side of the oriented metal substrate has a thickness of 5 to 80 nm.

The CeO ₂ layer provided on the oriented metal substrate side can sufficiently inherit the crystal orientation of the oriented metal substrate to the CeO ₂ layer, but if it is too thick, microcracks are generated, so the surface of the oriented metal substrate is caused by oxygen diffusion. There is a risk of oxidation. The preferred thickness is 5 to 80 nm, and more preferably 5 to 50 nm.

The invention according to claim 4
4. The substrate with an intermediate layer for a superconducting thin film wire according to claim 1, wherein the Y ₂ O ₃ layer has a thickness of 10 to 400 nm. 5.

The Y ₂ O ₃ layer needs to have a thickness that can sufficiently suppress oxygen diffusion to the surface of the oriented metal substrate, preferably 10 nm or more, and more preferably 50 nm or more. On the other hand, when the thickness exceeds 400 nm, the oxygen diffusion suppressing function is saturated, and therefore, the thickness is preferably 400 nm or less.

The invention described in claim 5
5. The superconducting thin film according to claim 1, wherein Δχ defined below is 110% or less of Δχ of each underlayer in each layer constituting the intermediate layer. 6. It is a board | substrate with an intermediate | middle layer for wires.
However, Δχ is the χ direction when X-rays are incident on the measurement object from the θ direction along the long direction and at a predetermined angle θ with the long direction, and the diffracted X-ray is detected by the two-dimensional detector. This is an index that expresses the half width of the peak in angle. Here, the χ direction indicates a direction perpendicular to the θ direction.

  Regarding the orientation of the intermediate layer or the like, conventionally, a value obtained by making X-rays incident on a measurement target and measuring the diffracted X-rays (X-ray diffraction method) has been used as an index indicating the orientation of the measurement target. Specifically, a sample is cut from a measurement target, the cut sample is placed on a sample stage, and measured while moving the position of incident X-rays, the sample, and the detector, Δω (out-of-plane orientation index), Δφ (In-plane orientation index) was used.

  However, when measuring these indicators, it is necessary to sample (cut out) the sample for measurement, and since only the orientation of the sampled portion is known, as an indicator of orientation in a long substrate with an intermediate layer, It was not always appropriate.

  Therefore, a method for continuously measuring the orientation was examined without requiring such sample sampling.

  As a result, in the measurement by the X-ray diffraction method described above, X-rays are incident on the measuring object along the longitudinal direction and from the θ direction that forms a predetermined angle θ with the longitudinal direction, and the diffracted X-rays are detected by a two-dimensional detector. It was found that the orientation could be measured continuously and appropriately by measuring the peak half width in the χ direction when detected, and the value representing the peak half width in angle was defined as Δχ. Here, the χ direction indicates a direction perpendicular to the θ direction.

  This index Δχ indicates that the smaller the value as in the above-described Δω and Δφ, the better the orientation, and unlike the measurement of Δω and Δφ, it is not necessary to rotate the sample or detector, so the orientation is improved. It can be easily and accurately grasped. In addition, by measuring while transporting in the longitudinal direction of the substrate with an intermediate layer, a sufficient number of crystal grains can be evaluated even on an oriented metal substrate having a large crystal grain size of 100 μm or more. Variations in orientation in the long direction can be known.

  Then, using such Δχ as an index, the index Δχ of each layer of the intermediate layer is within a certain range of Δχ of each underlayer, specifically, a range of 110% or less of each underlayer. By managing in this way, it is possible to provide a substrate with an intermediate layer for an oxide superconducting wire excellent in superconducting properties.

  In addition, the base layer with respect to the lowest layer of the layer which comprises an intermediate | middle layer points out an oriented metal substrate.

The invention described in claim 6
An oxide superconducting layer is formed on the substrate with an intermediate layer by a coating pyrolysis method using the substrate with an intermediate layer for a superconducting thin film wire according to any one of claims 1 to 5. This is a superconducting thin film wire.

By using CeO ₂ / YSZ / Y ₂ O ₃ / CeO ₂ as an intermediate layer having a four-layer structure, an oxide superconducting layer having a good crystal orientation can be stacked as described above. Even if it is a physical superconducting layer, Jc does not fall, and a high Ic superconducting thin film wire can be provided.

The invention described in claim 7
The superconducting thin film wire according to claim 6, wherein the coating pyrolysis method is a fluorine-free MOD method.

  As the MOD method, there are a TFA-MOD method using an organometallic compound containing fluorine in a raw material solution and a fluorine-free MOD method (FF-MOD method) using an organometallic compound not containing fluorine. Unlike the TFA-MOD method, it is preferable because it does not generate dangerous gas such as hydrogen fluoride gas, is environmentally friendly, and does not require processing equipment.

  According to the present invention, it is possible to provide a technique capable of obtaining an oxide superconducting wire excellent in superconducting characteristics by using the MOD method without causing a decrease in Jc even when a main-fired film is laminated.

It is sectional drawing which shows typically the structure of the board | substrate with an intermediate | middle layer for the superconducting thin film wire in one embodiment of this invention. It is sectional drawing which shows typically the structure of the superconducting thin film wire in one embodiment of this invention. It is sectional drawing which shows typically the structure of the board | substrate with an intermediate | middle layer for the conventional superconducting thin film wire.

  Hereinafter, the present invention will be specifically described based on embodiments.

1. First, a substrate with an intermediate layer for a superconducting thin film wire in the present embodiment will be described. FIG. 1 is a cross-sectional view schematically showing the configuration of a substrate with an intermediate layer for a superconducting thin film wire according to the present embodiment, in which 11 is an oriented metal substrate and 21 is an intermediate layer. The intermediate layer 21 has a four-layer structure including a CeO ₂ layer 21a, a Y ₂ O ₃ layer 21b, a YSZ layer 21c, and a CeO ₂ layer 21d.

(1) Oriented Metal Substrate As the oriented metal substrate 11, a long and flexible crystal oriented metal substrate is preferable. Specifically, Ni—Fe alloy, stainless steel, other alloys containing Ni, Cu and copper alloys, a clad substrate in which these are combined, etc., as described above, a clad substrate is preferable among these, In particular, for example, a Ni—Cu—SUS clad substrate in which a Ni layer is provided on a Cu base is preferable.

(2) Intermediate layer The intermediate layer 21 is formed with the CeO ₂ layer 21a, the Y ₂ O ₃ layer 21b, the YSZ layer 21c, and the CeO ₂ layer 21d in this order from the metal substrate 21 side using an RF sputtering method or the like. The thickness of each layer is preferably 5 to 50 nm, 50 to 400 nm, 100 to 400 nm, and 50 to 100 nm, respectively.

  In addition, it is preferable that the half width (Δχ) of the X-ray diffraction peak of each of the layers is 110% or less of the half width (Δχ) of the underlying layer of each layer.

2. Superconducting thin film wire Next, the superconducting thin film wire in the present embodiment will be described. FIG. 2 is a cross-sectional view schematically showing the configuration of the superconducting thin film wire in the present embodiment, and 22 is an oxide superconducting layer formed on the intermediate layer 21.

(1) Oxide Superconducting Layer The oxide superconducting layer 22 is preferably the REBCO (REBa ₂ Cu ₃ O _7-X : RE is a rare earth element) -based oxide superconducting layer. As RE, yttrium (Y), gadolinium (Gd), holmium (Ho), or the like is preferably used.

  Although the film thickness of the oxide superconducting layer 22 is appropriately set as necessary, it is preferably formed by the FF-MOD method as described above.

  In addition, when a thick film is required as the oxide superconducting layer 22, a coating film forming process for forming a coating film by applying and drying a raw material solution (MOD solution) and a calcination heat treatment process for thermally decomposing a metal organic compound And repeating the above and laminating a plurality of calcined films on the intermediate layer 21, followed by a main heat treatment. Thus, when a plurality of oxide superconducting layers (mainly calcined films) are laminated, The effect of the invention is more remarkably exhibited.

(2) Protective layer and stabilizing layer Next, after forming an Ag protective layer on the formed oxide superconducting layer 22, a Cu stabilizing layer is formed on the outer periphery to produce a superconducting thin film wire.

  Next, based on an Example, this invention is demonstrated more concretely. In this example, two oxide superconducting layers (fired films) were stacked.

1. Preparation of substrate with intermediate layer (1) Preparation of oriented metal substrate As oriented metal substrates, Ni / Cu / SUS clad substrates having a thickness of 3 μm, 20 μm and 100 μm, respectively (width 30 mm × length) 200 mm).

(2) Formation of intermediate layer
(Example)
Next, a four-layer structure of CeO ₂ / YSZ / Y ₂ O ₃ / CeO ₂ is formed on the Ni layer of the clad substrate using an RF sputtering method, and the thickness of each layer of CeO ₂ and YSZ on the surface side is 100 nm. The intermediate layers having the thicknesses shown in Table 1 were formed, with the thickness of each layer being constant at 200 nm and Y ₂ O ₃ and the thickness of each layer of CeO ₂ on the oriented metal substrate side.

(Comparative Example 1)
A substrate with an intermediate layer was produced in the same manner as in the example except that a three-layer structure of CeO ₂ / YSZ / Y ₂ O ₃ was used and the thickness of the Y ₂ O ₃ layer was changed to the thickness shown in Table 1.

(Comparative Example 2)
A substrate with an intermediate layer was produced in the same manner as in the example except that a three-layer structure of CeO ₂ / YSZ / CeO ₂ was used and the thickness of the CeO ₂ layer on the oriented metal substrate side was changed to the thickness shown in Table 1.

(Comparative Example 3)
The order of CeO ₂ (thickness 50 nm) and Y ₂ O ₃ layer (thickness 100 nm) was reversed to obtain a four-layer structure of CeO ₂ / YSZ / CeO ₂ / Y ₂ O _3. A layered substrate was produced.

2. Formation of oxide superconducting layer On the intermediate layer of each intermediate layer-attached substrate, by repeating the following procedure using the FF-MOD method, YBCO oxidation with a thickness of 0.5 μm, in which two layers of the fired film were laminated, A physical conductive layer was formed.

(1) Formation and calcination of coating film Each acetylacetonate complex of Y, Ba and Cu is adjusted so that the molar ratio of Y: Ba: Cu is 1: 2: 3 and the total metal ion concentration is 1 mol / L. The MOD solution is prepared by adjusting and dissolving in a solvent. After coating and drying on the substrate with the intermediate layer, the temperature is raised to 500 ° C. at a rate of 10 ° C./min. Held for 60 minutes and calcined. This operation was repeated twice to form a calcined film having a thickness of 2.5 μm.

(2) Main firing Next, the temperature was increased to 800 ° C. at a temperature increase rate of 50 ° C./min in an argon / oxygen mixed gas atmosphere having an oxygen concentration of 100 ppm, and then the main firing was carried out at the same temperature for 10 minutes. After the firing, the furnace was cooled in an atmosphere having an oxygen concentration of 100% to form a fired film having a thickness of 0.5 μm.

3. Evaluation (1) Evaluation of oxide superconducting wire (a) Evaluation of oxygen diffusion After forming the oxide superconducting layer, the peak intensity of NiO was measured using an X-ray diffraction method to evaluate the state of oxygen diffusion.

(B) Evaluation of crystal orientation The crystal orientation of the oxide superconducting layer was evaluated by Δχ obtained by continuously measuring a 10 cm section using the X-ray diffraction method described above. Note that Cu was used as the X-ray source, and measurement was performed by the θ-2θ method. A spherical detector was used as the detector.

(C) Evaluation of superconducting characteristics Jc was measured at a temperature of 77K using a four-terminal method to evaluate the superconducting characteristics.

(D) Evaluation results Table 1 summarizes the evaluation results with intermediate layers of Examples 1 to 13 and Comparative Examples 1 to 3.

From Table 1, Examples 1 to 13 in which an intermediate layer having a four-layer structure of CeO ₂ / YSZ / Y ₂ O ₃ / CeO ₂ was provided from the surface side, and CeO ₂ / YSZ / Y ₂ O from the surface side. _In the case of Comparative Example 1 in which an intermediate layer having a three-layer structure of 3 was provided, compared to the case of Comparative Example 2 in which an intermediate layer having a three-layer structure of CeO ₂ / YSZ / CeO ₂ was provided from the surface side, It can be seen that oxygen diffusion is reduced.

  Further, in the case of Examples 1 to 13, it can be seen that Δχ is small and the crystal orientation of the oxide superconducting layer is high as compared with Comparative Examples 1 and 3.

  In the case of Example 1 to Example 13, as compared with any of Comparative Examples 1 to 3, Jc is high, oxygen diffusion is small, and crystal orientation is high. Can be seen to improve.

Furthermore, from Table 1, among the examples, when the thicknesses of the Y ₂ O ₃ layer and the CeO ₂ layer were 100 to 200 nm and 5 to 50 nm, respectively (Examples 3, 4, 7, and 8), Jc was particularly high. It can be seen that it has particularly excellent superconducting properties.

Further, when Example 8 and Comparative Example 3 having the same thickness of the Y ₂ O ₃ layer and the CeO ₂ layer are compared, the crystal orientation becomes higher in Example 8 in which the CeO ₂ layer is provided on the oriented metal substrate side. On the other hand, in Comparative Example 3 in which the Y ₂ O ₃ layer is provided on the oriented metal substrate side, the crystal orientation is low and Jc is also low. From this result, it is understood that the order of forming the Y ₂ O ₃ layer and the CeO ₂ layer is important in the intermediate layer having the four-layer structure.

From this result, it can be seen that by providing an intermediate layer having a four-layer structure of CeO ₂ / YSZ / Y ₂ O ₃ / CeO ₂ from the surface side, oxygen diffusion is small and crystal orientation is enhanced.

(2) Evaluation of substrate with intermediate layer (a) Evaluation method Substrate with intermediate layer of Examples 14 to 16 in the same manner as in Example 4 except that the sputtering conditions were changed and the crystallinity of each layer was changed. Was made. Then, Δχ of each of the oriented metal substrate and each intermediate layer was measured, and the ratio of the underlayer to Δχ was obtained.

  Moreover, the board | substrate with an intermediate | middle layer of Examples 17-19 was similarly produced with respect to the board | substrate with an intermediate | middle layer of Example 7, and the same measurement was performed.

(B) Evaluation results Table 2 shows the measurement results of Examples 4 and 14 to 16, and Table 3 shows the measurement results of Examples 7 and 17 to 19.

  From Table 2, Example 4 and Examples 14 to 16 all show high Jc, but Examples 4 and 14 in which the ratio of Δχ to the underlayer is 110% or less are all relative to the underlayer. It can be seen that Jc is higher than Examples 15 and 16 in which a part of the ratio Δχ exceeds 110%.

  Similarly, Example 7 and Examples 17 to 19 all show high Jc from Table 3, but Examples 7 and 17 in which the ratios of Δχ to the underlayer are all 110% or less are as follows. It can be confirmed that Jc is higher than those of Examples 18 and 19 in which a part of the ratio of Δχ to the underlayer exceeds 110%.

  As described above, it was confirmed that an oxide superconducting wire excellent in superconducting characteristics can be provided by controlling the ratio of Δχ to the base layer to be 110% or less.

  While the present invention has been described based on the embodiments, the present invention is not limited to the above embodiments. Various modifications can be made to the above-described embodiments within the same and equivalent scope as the present invention.

1, 3 Substrate with intermediate layer 2 Superconducting thin film wire 11 Oriented metal substrate 21, 31 Intermediate layer 21a CeO ₂ layer 21b Y ₂ O ₃ layer 21c YSZ layer 21d CeO ₂ layer 22 Oxide superconducting layer 31a Seed layer (seed film layer)
31b Barrier layer (diffusion prevention layer)
31c Cap layer (lattice matching layer)

Claims (7)

A substrate with an intermediate layer used when producing a superconducting thin film wire by a coating pyrolysis method,
An intermediate layer is provided on the oriented metal substrate,
A superconducting thin film characterized in that the intermediate layer has a four-layer structure of a CeO ₂ layer, a YSZ layer, a Y ₂ O ₃ layer, and a CeO ₂ layer in order from the surface side to the oriented metal substrate side. Substrate with an intermediate layer for wire.   2. The substrate with an intermediate layer for a superconducting thin film wire according to claim 1, wherein the oriented metal substrate is a clad substrate. 3. The substrate with an intermediate layer for a superconducting thin film wire according to claim 1, wherein the CeO ₂ layer on the side of the oriented metal substrate has a thickness of 5 to 80 nm. 4. The substrate with an intermediate layer for a superconducting thin film wire according to claim 1, wherein the Y ₂ O ₃ layer has a thickness of 10 to 400 nm. 5. 5. The superconducting thin film according to claim 1, wherein Δχ defined below is 110% or less of Δχ of each underlayer in each layer constituting the intermediate layer. 6. Substrate with an intermediate layer for wire.
However, Δχ is the χ direction when X-rays are incident on the measurement object from the θ direction along the long direction and at a predetermined angle θ with the long direction, and the diffracted X-ray is detected by the two-dimensional detector. This is an index that expresses the half width of the peak in angle. Here, the χ direction indicates a direction perpendicular to the θ direction.   An oxide superconducting layer is formed on the substrate with an intermediate layer by a coating pyrolysis method using the substrate with an intermediate layer for a superconducting thin film wire according to any one of claims 1 to 5. A superconducting thin film wire.   The superconducting thin film wire according to claim 6, wherein the coating pyrolysis method is a fluorine-free MOD method.

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