JP2002075079A - High-temperature superconducting thick-layer material and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-temperature superconducting thick-layer material which permits long thick-layer wire material and large-area thick layer material of high superconducting characteristic, which material has heretofore been too difficult to be manufacutred, and the method for manufacturing the same. SOLUTION: A crystalline intermediate layer 2 having a thickness larger than or equal to 0.1 μm and smaller than or equal to 3 μm is formed on a substrate 1. On this intermediate layer 2, a crystalline superconducting thick layer having a thickness larger than or equal to 0.5 μm and smaller than or equal to 30 μm is formed by an application/thermal-decomposition method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-temperature superconducting thick film member and a method for manufacturing the same, and more particularly, to a high critical current having excellent superconducting characteristics, a uniform composition and structure, and a practically useful value. The present invention relates to a high-temperature superconducting thick-film member that can be carried and has a long or large area and is particularly suitable for electric power use and a method for manufacturing the same.

[0002]

2. Description of the Related Art A high-temperature superconducting thin film is formed by a sputtering method,
Due to the application of physical vapor deposition techniques cultivated in the conventional semiconductor industry, such as the thermal co-evaporation method, the electron beam evaporation method, and the laser evaporation method, practical application development is progressing. Especially the critical temperature is 90K
(Yttrium) 123-based structure or RE
In a high-temperature superconducting thin film having a (rare earth) 123-based structure,
Critical temperature exceeding liquid nitrogen temperature (77K) or 10 ⁵ A /
A critical current characteristic exceeding cm ² (77 K, under a self-magnetic field) was confirmed, and a characteristic completely surpassing a Bi (bismuth) -based silver-coated high-temperature superconducting wire which has been put into practical use at a laboratory level has been confirmed.

[0003] Using such a high-temperature superconducting thin film, a prototype of a microwave filter used for a mobile communication base station, which is intended for practical use, is called a SQUID (Super conducting Quan).
The development of prototypes such as magnetocardiographs using the ntumInterference Device phenomenon and the development of elements aimed at high-speed computers using the Josephson effect are progressing rapidly, and cost is lower than that of conventional ordinary conducting equipment. After confirming the performance and long-term reliability, it is expected that commercialization will proceed.

[0004] On the other hand, the development of prototypes of so-called power applications such as current limiters for cables and magnets is being promoted by utilizing the "electric resistance = 0" phenomenon of superconductivity. If an underground cable using a high-temperature superconducting wire can be realized, the existing small diameter (150 to 2
Compact that can be laid in tunnels
Large capacity cables can be constructed. As a result, it is possible to transmit more than three times the power of conventional systems, eliminating the need for huge underground construction costs in large cities such as Tokyo.
The development is being actively pursued because of the cost merit.

[0005] In addition, Y-based and RE-based thin film wires
The magnetic field characteristics of K are much better than Bi-based silver-coated wires. For this reason, if the length of the wire becomes longer and a predetermined performance can be achieved at an appropriate cost, for example, the MRI (Magnetic Resonance Imagin) which is being applied to a metal-based superconducting wire is being advanced.
Y) and RE thin film wires are promising as wires for g) and superconducting magnets for silicon single crystal pulling furnaces. Also, SN dislocation type current limiters using thin films have been studied, and compact and high-performance current limiters that cannot be realized with a Bi-based silver-coated wire whose matrix is a stabilizing material have been developed. Whether it can be realized in a system thin film is also being studied.

[0006]

The physical vapor deposition method is characterized in that the compositional deviation of a high-temperature superconducting film formed from a raw material target is small, and the film forming rate is relatively high even in the vapor phase growth method. For this reason, a sputtering method or a laser deposition method has been applied for the purpose of verifying the principle of a thin film having excellent characteristics. However, current lasers and sputtering devices have a problem that the power is small in mass-producing thin-film superconducting wires and large-area thin films.

[0007] In electronic applications such as SQUIDs and electronic computers, it is possible to commercialize if a high-performance film can be uniformly produced even in a small amount, but the production cost with a physical vapor deposition apparatus is high, which is fundamental to practical use. There was a problem.

On the other hand, in the field of power application, a process capable of producing a large amount of thin films at a low cost is particularly necessary. However, the physical vapor deposition method is limited to an experimental method for verifying the principle due to the low output of the power of the vapor deposition apparatus. . This is because the prospect of increasing the output of a laser source or a sputter source having a large output required for the physical vapor deposition of a high-temperature superconducting thin film is limited in the future.

At present, for example, only an industrial laser having an output of at most about 200 W has been commercialized as a laser source. For this reason, it is in principle difficult to produce a superconducting film having a thickness of 5 μm or more on a tape substrate having a width of 10 mm at a film forming speed of 10 m / H or more.

As a technique capable of producing a large amount of Y-based superconducting thin films, there is a coating thermal decomposition method disclosed in Japanese Patent Publication No. 4-76324, Japanese Patent Publication No. 4-76323, and the like. This method has the advantage that a thick film on a wire or a single crystal substrate can be obtained relatively easily using a simpler device than the physical vapor deposition method. Has a drastic disadvantage that the critical current density is low.

For example, on a single crystal, 10 ⁵ to 10 ⁶ A /
Jc of about ² cm (77K, 0T) is obtained,
In the case of a large-area film, cracking and composition deviation of the film occur, so that it is difficult to make the large-area film. Cracks are generated due to a difference in thermal expansion between the substrate and the superconducting thick film or a crystal mismatch. In addition, the composition deviation is caused by incomplete epitaxial growth from the substrate, generation of holes generated when unnecessary substances are vaporized in the process of single crystallization by heat treatment, and the like.

Further, the superconducting film is not oriented on the polycrystalline metal substrate, and J ^{4 of} the 10 ⁴ A / cm ² (77K, 0T) class is used.
c. The reason for the low Jc is that the superconducting thick film grown from the polycrystalline substrate is not oriented in one direction in the plane. As a result, there is no technique for a Y-based superconducting thin film that achieves both high characteristics and a thick film or mass productivity, and it has been considered that it is difficult to apply the Y thin film to power applications such as superconducting cables and current limiters. .

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a high-temperature superconducting thick-film member capable of forming a long thick-film wire or a large-area thick film having high superconducting characteristics, which has been difficult in the past, and a method of manufacturing the same. .

[0014]

According to one aspect of the present invention, there is provided a high-temperature superconducting thick film member comprising: a substrate; a monocrystalline intermediate layer;
And a single-crystal superconducting thick film. The substrate has a main surface and is made of single crystal or polycrystal. The intermediate layer is formed on the main surface of the substrate and has a thickness of 0.1 μm or more and 3 μm or more.
m or less. The superconducting thick film is formed on the intermediate layer by a coating pyrolysis method, and has a thickness of 0.5 μm to 30 μm.
It has the following thickness.

According to the high-temperature superconducting thick film member according to one aspect of the present invention, by providing the intermediate layer, the thermal expansion coefficient of the intermediate layer can be made closer to the superconducting thick film than the substrate. As a result, the difference in thermal expansion between the substrate and the superconducting thick film can be reduced, cracks in the film can be prevented, and large-area film formation is facilitated.

Further, the lattice constant of the intermediate layer can be made closer to that of the superconducting thick film than that of the substrate, whereby lattice distortion due to a crystal mismatch between the substrate and the superconducting thick film can be reduced. This also prevents cracks in the film and facilitates large-area film formation.

Further, since the intermediate layer can be formed by a physical vapor deposition method or the like, the crystal orientation of the intermediate layer can be improved. For this reason, even if the superconducting thick film is formed by the coating pyrolysis method, the crystal orientation of the superconducting thick film can be improved, and a large critical current density can be obtained.

Accordingly, a long thick film wire and a large area thick film having high superconducting characteristics, which have been difficult in the past, can be realized.

The thickness of the intermediate layer is 0.1 μm or more.
The reason why the thickness is set to 0 μm or less is that if it is less than 0.1 μm, a film having good orientation cannot be obtained, and if it exceeds 3.0 μm, the crystal orientation decreases. In addition, the thickness of the superconducting thick film is set to 0.5 μm or more and 30 μm or less because the thickness of 0.5 μm or more can be easily formed by using the coating pyrolysis method, and if it exceeds 30 μm, the crystal orientation decreases. Because it comes.

When forming a superconducting thin film, the crystal axis is
There is a property that "they are easily aligned in the direction of the c-axis, but are hardly aligned in the direction of the in-plane ab-axis". For this reason, in the present application, the “single-crystal” crystal means a crystal “having the in-plane ab axis aligned with the c-axis, that is, the directions of all the crystal axes are aligned”.

Preferably, in the above aspect, the intermediate layer has a thermal expansion coefficient closer to that of the superconducting thick film than that of the substrate, and is larger than the lattice constant of the substrate. It has a lattice constant close to the lattice constant.

As a result, similarly to the above, a long thick film wire and a large area thick film having high superconducting characteristics, which have been difficult in the past, can be realized.

In the above aspect, preferably, a single-crystal superconducting seed film is further provided between the intermediate layer and the superconducting thick film.

Since the superconducting seed film functions to generate nuclei during epitaxial growth, it becomes possible to epitaxially grow a superconducting thick film on the intermediate layer.

In the above aspect, the intermediate layer preferably has a single-layer or multilayer structure containing at least one oxide selected from the group consisting of zirconium, ytterbium, yttrium and cerium.

As described above, the material of the intermediate layer can be appropriately selected. Preferably, in the above aspect, the intermediate layer has a crystal structure obliquely inclined at an angle of 10 ° or less with respect to the main surface of the substrate, and the in-plane orientation has an inclination angle of 3 °.
0 ° or less.

Thus, good crystal orientation can be obtained. A high-temperature superconducting thick-film member according to another aspect of the present invention includes a substrate, a single-crystal superconducting seed film, and a single-crystal superconducting thick film. The substrate has a main surface and is made of single crystal or polycrystal. The superconducting seed film is formed on the main surface of the substrate. The superconducting thick film is formed on the superconducting seed film by a coating pyrolysis method and has a thickness of 0.5 μm or more.
It has a thickness of 0 μm or less.

According to the high-temperature superconducting thick film member according to another aspect of the present invention, a complicated heat treatment method is required in the coating pyrolysis method, but by applying this superconducting seed film,
It becomes easier to form a thick film with less composition deviation than when there is no superconducting seed film, and it is also possible to lower the temperature of the crystallization process. Furthermore, it has been found that single crystallization of the superconducting thick film by complicated heat treatment may not be necessary. This allows
Even if there is no intermediate layer, the composition shift of the superconducting thick film can be prevented, so that a large-area film can be formed.

Thus, a long thick-film wire or a large-area thick film having high superconducting characteristics, which has conventionally been difficult, can be obtained.

In the above other aspects, preferably, the material of the superconducting seed film and the superconducting thick film has a REBCO123 structure and contains different RE elements as constituent elements.

By changing the superconducting composition of the superconducting seed film and the superconducting thick film and the constituent rare earth elements so as to increase the melting point of the superconducting seed film, heat treatment for forming a single crystal of the superconducting thick film can be performed. Also in the above, the seed crystal becomes a starting point of nucleation without causing crystal decomposition, and the single crystal of the superconducting thick film becomes easy.

Note that "REBCO1" in the specification of the present application.
The 23 structures ", in _{RE x Ba y Cu z O 7} -d, 0.
7 ≦ x ≦ 1.3, 1.7 ≦ y ≦ 2.3, 2.7 ≦ z ≦
3.3.

In the above other aspect, preferably, the melting point of the superconducting seed film is higher than the melting point of the superconducting thick film.

Thus, even in the heat treatment for single crystallizing the superconducting thick film, the seed crystal becomes a starting point of nucleation without causing crystal decomposition, and the single crystal of the superconducting thick film is easily formed.

Preferably, in the above one and other aspects, the material of the single crystal substrate contains at least one selected from the group consisting of sapphire, lanthanum aluminate, magnesium oxide and strontium titanate.

As described above, the material of the substrate can be appropriately selected. Preferably in the above one and other aspects, the material of the polycrystalline substrate is stainless steel, Hastelloy,
A flexible metal containing at least one selected from the group consisting of nickel, copper and aluminum, and having a thickness of 200 μm or less.

As described above, the material of the polycrystalline substrate can be appropriately selected. Preferably in the above one and other aspects, the superconducting thick film has a REBCO123 structure, and the RE element includes holmium.

A method of manufacturing a high temperature superconducting thick film member according to one aspect of the present invention includes the following steps.

First, a monocrystalline intermediate layer having a thickness of 0.1 μm or more and 3 μm or less is formed on the main surface of a substrate made of a single crystal or polycrystal. Then, on the intermediate layer, 0.
A single-crystal superconducting thick film having a thickness of 5 μm or more and 30 μm or less is formed using a coating pyrolysis method.

According to the method for manufacturing a high-temperature superconducting thick film member according to one aspect of the present invention, by providing the intermediate layer, the coefficient of thermal expansion of the intermediate layer is made closer to the superconducting thick film than the substrate. Can be. As a result, the difference in thermal expansion between the substrate and the superconducting thick film can be reduced, cracks in the film can be prevented, and large-area film formation is facilitated.

Further, the lattice constant of the intermediate layer can be made closer to that of the superconducting thick film than that of the substrate, so that lattice distortion caused by a crystal mismatch between the substrate and the superconducting thick film can be reduced. Therefore, from this point as well, cracks in the film can be prevented, and a large-area film can be easily formed.

Further, since the intermediate layer can be formed by a physical vapor deposition method or the like, the crystal orientation of the intermediate layer can be improved. For this reason, even if the superconducting thick film is formed by the coating pyrolysis method, the crystal orientation of the superconducting thick film can be improved, and a large critical current density can be obtained.

Therefore, it is possible to manufacture a long thick film wire or a large area thick film having high superconducting characteristics, which has been difficult in the past.

In the above one aspect, preferably, a single-crystal superconducting seed film is formed by a physical vapor deposition method after the formation of the intermediate layer and before the formation of the superconducting thick film.

Since this superconducting seed film fulfills the function of nucleation during epitaxial growth, it becomes possible to epitaxially grow a superconducting thick film on the intermediate layer.

Preferably, in the above aspect, the intermediate layer is formed by a physical vapor deposition method. Thereby, the crystal orientation of the intermediate layer can be improved, and the crystal orientation of the superconducting thick film can be improved even when the superconducting thick film is formed by a coating pyrolysis method, and a large critical current density can be obtained. Obtainable.

In one aspect, the intermediate layer is preferably formed by a laser ablation method in which a material is irradiated with a laser beam to deposit a substance scattered from the material on the main surface of the substrate.

Thus, a self-oriented intermediate layer can be obtained. Preferably, in the above one aspect, the intermediate layer is formed by performing a laser ablation method in a state where the main surface of the substrate is inclined with respect to the surface of the raw material to which the laser light is irradiated.

As described above, the substrate inclined film forming method (ISD: Incl
The use of ined substrate deposition enables the formation of a single crystalline intermediate layer to enable formation of a superconducting thick film even on various substrates having random crystal orientations. In this case, the intermediate layer has two new functions of preventing the diffusion of elements from the substrate and the crystal orientation of the superconducting thick film, in addition to the relaxation of the crystal lattice distortion.

In the above aspect, the intermediate layer is preferably formed by a coating thermal decomposition method alone, or formed by a coating thermal decomposition method followed by single crystallization by a laser annealing method.

According to this method, the intermediate layer can be monocrystallized to improve the crystal orientation.

In the above one aspect, preferably, the substrate has a linear shape, and one end of the substrate is wound around a first roll and the other end is wound around a second roll, so that the substrate has a linear shape. Then, an intermediate layer and a superconducting thick film are sequentially formed.

This makes it possible to form each film in the longitudinal direction of the linear substrate. In the above aspect, preferably, the size of the substrate is 100 cm ² or more, and at least one of the intermediate layer and the superconducting thick film is formed while swinging or rotating the substrate.

Thus, each film can be formed even on a substrate having a large area of 100 cm ² or more.

A method for manufacturing a high-temperature superconducting thick film member according to another aspect of the present invention includes the following steps.

First, a single-crystal superconducting seed film is formed on the main surface of a single-crystal or polycrystal substrate by physical vapor deposition. Then, on the superconducting seed film, at least 0.5 μm
A single crystalline superconducting thick film having a thickness of not more than μm is formed by using a coating pyrolysis method.

In the coating thermal decomposition method, a complicated heat treatment method is required. By providing this superconducting seed film,
It becomes easier to form a superconducting thick film having less composition deviation than when there is no superconducting seed film, and it is also possible to lower the temperature of the crystallization process. Furthermore, it has been found that single crystallization of the superconducting thick film by complicated heat treatment may not be necessary. Accordingly, the composition deviation of the superconducting thick film can be prevented even without the intermediate layer, so that a large-area film can be formed.

Therefore, it is possible to manufacture a long thick-film wire or a large-area thick film having high superconducting characteristics, which has been difficult in the past.

In the above other aspect, preferably, the substrate has a linear shape, and one end of the substrate is wound around a first roll and the other end is wound around a second roll, so that the substrate is formed on the substrate. Then, a superconducting seed film and a superconducting thick film are sequentially formed.

This makes it possible to form each film in the longitudinal direction of the linear substrate. In the above other aspect, preferably, the size of the substrate is 100 cm ² or more, and at least one of the superconducting seed film and the superconducting thick film is formed while swinging or rotating the substrate.

As a result, each film can be formed even on a large-area substrate of 100 cm ² or more.

In the above-mentioned and other aspects, preferably, the step of forming a single-crystal superconducting thick film by using a coating thermal decomposition method comprises forming the superconducting thick film by using a coating thermal decomposition method, and then forming the single-crystal superconducting thick film by using a laser annealing method. And a step of converting

According to this method, the superconducting thick film can be monocrystallized to improve the crystal orientation.

In the above one and other aspects, preferably, the annealing source in the laser annealing method is 0.1.
Excimer laser having a wavelength of not less than 0.5 μm and not more than 0.5 μm or YA having a wavelength of not less than 0.5 μm and not more than 2 μm
G (Yttrium-Aluminum Garnet) laser.

As described above, the annealing source can be appropriately selected. Preferably in the above one and other aspects,
The superconducting thick film is subjected to at least four processes of temporary sintering, main sintering, post annealing and oxygen annealing.

Thus, a superconducting thick film having high superconducting characteristics can be obtained. In the above one and other aspects, preferably, the raw material in the coating pyrolysis method contains an organometallic raw material.

In the case of the organometallic raw material, the energy required for dissociation into atoms and molecules necessary for forming a superconducting thin film is obtained by sintering a mixture of carbonates and oxides, which is a conventional raw material, or a raw material formed by sintering the mixture. Dramatically smaller than raw materials containing single crystals that have been melted and solidified. Therefore, by using the organometallic raw material, it becomes possible to crystallize the superconducting thick film by a relatively simple heat treatment process. Note that various organic acids can be used as the solvent.

In the above and other aspects, preferably, a superconducting thick film is formed on both surfaces of the substrate.

As a result, high superconducting characteristics can be obtained on both surfaces of a long wire or a large-area substrate.

[0070]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view schematically showing a configuration of a high-temperature superconducting thick film member according to an embodiment of the present invention.
Referring to FIG. 1, high-temperature superconducting thick-film member 5 includes a substrate 1 made of single crystal or polycrystal, a monocrystalline intermediate layer 2 formed on the main surface of the substrate, and a monocrystalline intermediate layer 2 formed on intermediate layer 2. And a single-crystal superconducting thick film 3.

The intermediate layer 2 has a thickness T2 of 0.1 μm or more and 3 μm or less, and the superconducting thick film 3 has a thickness of 0.5 μm or more and 30 μm or less.
It has a thickness T3 of not more than μm. The superconducting thick film 3 is formed by a coating pyrolysis method.

The intermediate layer 2 has a coefficient of thermal expansion closer to that of the superconducting thick film 3 than the coefficient of thermal expansion of the substrate 1, and has a lattice closer to the lattice constant of the superconducting thick film 3 than the lattice constant of the substrate 1. Has a constant.

The intermediate layer 2 is formed on the main surface of the substrate 1 by 10
It has a structure made of a crystal 2a which is obliquely inclined at an angle θ of not more than °. The inclination angle of the in-plane orientation is 30 °.
It is as follows. Here, the “inclination angle of in-plane orientation” means “peak half-width in X-ray pole figure measurement”, and the smaller this value, the sharper the peak in X-ray measurement, ie, Has good orientation.

When the substrate 1 is a single crystal, the material of the substrate 1 is
Sapphire, lanthanum aluminate, magnesium oxide and strontium titanate are preferably used alone or in any combination thereof. When the substrate 1 is polycrystalline, the material of the substrate 1 is preferably a single metal of stainless steel, Hastelloy, nickel, copper and aluminum or any combination thereof, and is a flexible metal having a thickness of 200 μm or less.

The material of the intermediate layer is a single layer of a single element oxide selected from zirconium, ytterbium, yttrium and cerium, or a single layer of a composite oxide thereof, or a multi-layer structure of a single element or multi-element material thereof. Preferably, there is.

A single-crystal superconducting seed film 4 may be formed between the intermediate layer 2 and the superconducting thick film 3 as shown in FIG. 2, or as shown in FIG. Instead of a monocrystalline superconducting seed film 4 between the substrate 1 and the superconducting thick film 3
May be formed.

The material of the superconducting seed film 4 and the material of the superconducting thick film 3 shown in FIGS. 2 and 3 may be the same, but both have a REBCO123 structure and different REs.
It is preferable to include a (rare earth) element as a constituent element.
It is preferable that the material of the superconducting seed film 4 is selected so that the melting point of the superconducting seed film 4 is higher than the melting point of the superconducting thick film 3.

The material of the superconducting thick film 3 is REBCO1
Preferably, it has a 23 structure, and the RE (rare earth) element contains holmium.

Next, the manufacturing method of this embodiment will be described. FIG. 4 is a diagram illustrating a method for manufacturing a high-temperature superconducting thick-film member according to one embodiment of the present invention. Referring to FIG. 4, first, substrate 1 made of single crystal or polycrystal is prepared, and intermediate layer 2 is formed on substrate 1 (step S1). Thereafter, the superconducting thick film 3 is formed by the coating pyrolysis method, and the high-temperature superconducting thick film member 5 is manufactured. In this coating thermal decomposition method, first, a solution is prepared by dissolving a metal organic compound as an organic metal raw material in an organic solvent.
2). Thereafter, the solution is applied onto the intermediate layer 2 and then dried to form a thick film of the metal-containing compound (Step S3). Superconducting thick film 3 is formed by heating and firing the thick film of the metal-containing compound.
4) A high temperature superconducting thick film member 5 is obtained.

The intermediate layer 2 is formed with a thickness of 0.1 μm or more and 3 μm or less, and the superconducting thick film 3 is formed with a thickness of 0.5 μm or more and 30 μm or less.
m or less.

Incidentally, the step of forming the intermediate layer 2 (step S
After 1), a superconducting thick film forming step (step S
Before 2 to S4), it is preferable that a single-crystal superconducting seed film 4 made of a material different from that of the superconducting thick film 3 is formed on the intermediate layer 2 by physical vapor deposition.

The intermediate layer 2 is preferably formed by a physical vapor deposition method. In this physical vapor deposition method, a laser ablation method is used in which a raw material is irradiated with a laser beam to vapor-deposit a substance scattered from the raw material on a main surface of a substrate. Method. Further, in this laser ablation method, as shown in FIG.
It is preferable that the process is performed in a state where the main surface of the substrate 11 is tilted by a predetermined angle α with respect to the surface to which 3 is irradiated. In this case, a predetermined portion of the substrate 1 may be covered with the mask 12.

As a process of the substrate tilted laser vapor deposition method (FIG. 5), in an oxygen atmosphere of, for example, about 100 mTorr, a beam is drawn and sintered by an optical system in order to realize high-density laser light using an excimer laser. The body target 11 is irradiated with the laser beam 13 at an energy density of 1 to 5 J / cm ² to cause ablation. The as-deposited film is generated by applying plasma generated by the ablation to the substrate 1 while heating the substrate 1. At the time of film formation, a basic single crystalline structure is formed.

By forming the intermediate layer 2 using such a physical vapor deposition method, for example, yttria-stabilized zirconia (YSZ) or oxidized oxide is formed on a flexible metal substrate 1 having excellent oxidation resistance such as Hastelloy or heat-resistant stainless steel. An oxide such as cerium (CeO ₂ ) can be formed.

In addition to film forming methods other than the laser vapor deposition method, physical vapor deposition methods such as sputtering and electron beam, and CVD methods
(Chemical Vapor Deposition)
A solution method such as an OD (Metal Organic Deposition) method may be used. Further, the intermediate layer 2 may be formed by a coating thermal decomposition method alone, or may be formed by a single crystallization by a laser annealing method after being formed by the coating thermal decomposition method.

In FIG. 4, a superconducting seed film 4 may be formed instead of the intermediate layer 2 (step S1). In this case, the superconducting thick film 3 is formed on the superconducting seed film 4. (Steps S2 to S4).

The material of the superconducting seed film 4 is
The element is not limited, but considering the characteristics at 77K
Indicates that the YBCO123 structure or REBCO123 structure
Is also a preferred application object. Laser deposition process
For example, a YBCO123 structure and a REBC
In the case of a superconducting thin film having an O123 structure, 100 mTorr
Use an excimer laser in a low oxygen atmosphere of about r
Optical system to achieve high-density laser light.
1-5J / cm ^TwoEnergy
Ablation by irradiating laser at lugi density
And heat the substrate to about 600 to 800 ° C.
Apply the plasma generated by the ablation to the substrate.
As a result, an as-deposited film is generated,
A fundamental superconducting crystal structure is formed.

As a method of forming a single-crystal superconducting thick film by using a coating thermal decomposition method, a method of forming a superconducting thick film by a coating thermal decomposition method and then performing single crystallization by a laser annealing method may be used. Good.

As a specific type of laser used in the laser annealing method, an excimer laser or a YAG laser is practical. The wavelength of an excimer laser depends on the type of gas used,
It is 0.1 μm or more and 0.5 μm or less. See F ₂
At 157 nm, ArF at 193 nm, KrF at 248 n
m, XeCl of 308 nm and XeF of 351 nm have been realized.
W. The wavelength of the YAG laser is 0.5 μm or more2
μm or less, typically 1.06 μm. YA
In recent years, with the development of semiconductor crystals, the development of large-power and long-period oscillation has been rapidly progressing, and a G laser having a power of 3 kW by LD excitation has been sold at present. The high-power laser is not limited to YAG, but may be a carbon dioxide laser (10.6 μm) or the like. The short-wavelength laser is not limited to the excimer laser, and is not limited to the excimer laser as long as a laser of 0.5 μm or less and several hundred W class can be used.

When the substrate 1 has a linear shape (including a tape shape), one end is wound around a roll 21 and the other end is wound with a roll 22 as shown in FIG. Then, the intermediate layer 2 or the superconducting seed film 4 may be formed on the substrate 1, and the superconducting thick film 3 may be formed in the chamber 24.

When the size of the substrate 1 is 100 cm ² or more, the substrate 1 is rocked as shown in the direction of the arrow in FIG. 2 or a superconducting seed film 4 and a superconducting thick film 3 are preferably formed.

It is preferable that the superconducting thick film 3 is subjected to at least four treatments of temporary sintering, main sintering, post annealing and oxygen annealing, and the superconducting thick film 3 is formed on both surfaces of the substrate 1. May be done.

[0094]

Embodiments of the present invention will be described below.

Example 1 An intermediate layer of cerium oxide was formed on a sapphire single crystal substrate by a laser ablation method. The thickness of the intermediate layer was 1 μm.

On this intermediate layer, YBa ₂ C
A superconducting thick film represented by the composition of u ₃ O _7-d was formed. The starting material is prepared by dissolving a naphthenate of each element in an ethanol solvent so that the composition ratio of Y: Ba: Cu is 1: 2: 3, and then applying, heat-treating, and oxygen annealing to perform superconductivity. A thick film was formed. The thickness and critical current density of the formed superconducting film were measured. Table 1 shows the relationship between the thickness of the superconducting film and the critical current density.

[0097]

[Table 1]

From the results shown in Table 1, when a predetermined intermediate layer is formed by the laser ablation method and a superconducting thick film is formed by the coating pyrolysis method, the superconducting thick film having a thickness of 0.5 μm to 30 μm is excellent. It has been found that characteristics can be obtained.

Example 2 An intermediate layer of cerium oxide was formed on a sapphire single crystal substrate by a laser ablation method. The thickness of the intermediate layer was 1 μm. YBa ₂ C is formed on the intermediate layer by using a laser ablation method.
A superconducting seed film represented by the composition of u ₃ O _7-d was formed. The thickness of the superconducting seed film was 1 μm.

Further, a superconducting thick film represented by the composition of YBa ₂ Cu ₃ O _7-d was formed on the superconducting seed film by a coating thermal decomposition method. The starting material has a composition ratio of Y: Ba: Cu of 1:
A solution in which naphthenates of each element were dissolved in an ethanol solvent so as to have a ratio of 2: 3 was prepared and subjected to coating, heat treatment and oxygen annealing to form a superconducting thick film. The thickness and critical current density of the formed superconducting film were measured. Table 2
2 shows the relationship between the thickness of the superconducting film formed by the coating pyrolysis method and the critical current density.

[0101]

[Table 2]

According to the results shown in Table 2, if a predetermined intermediate layer is formed by the laser ablation method, a superconducting seed film is formed by the laser ablation method, and a superconducting film is formed thereon by the coating thermal decomposition method. It has been found that excellent superconducting characteristics can be obtained in a superconducting thick film having a thickness of 0.5 μm or more and 30 μm or less.

Example 3 An intermediate layer of cerium oxide was formed on a sapphire single crystal substrate by a laser ablation method. The thickness of the intermediate layer was 1 μm. YBa ₂ C is formed on the intermediate layer by using a laser ablation method.
A superconducting seed film represented by the composition of u ₃ O _7-d was formed. The thickness of the superconducting seed film was 1 μm.

On this superconducting seed film, a solution in which a naphthenate of each element was dissolved in an ethanol solvent so as to have a composition ratio of Y: Ba: Cu of 1: 2: 3 as a starting material was prepared and applied. did. When the laser is applied to the coated surface, the solvent on the coated surface is removed and crystallization occurs.
A superconducting thick film was formed. The laser used at this time was a KrF excimer laser having a wavelength of 248 nm, and the applied surface was irradiated with a laser energy density of 0.1 J / cm ² .
The film thickness and critical current density of the superconducting film formed by this laser irradiation were measured. Table 3 shows the relationship between the thickness of the superconducting film and the critical current density.

[0105]

[Table 3]

According to the results shown in Table 3, after a predetermined intermediate layer was formed by the laser ablation method, a superconducting seed film was formed by the laser ablation method, and further, a solution of a superconducting material applied thereon was irradiated with a laser. It has been clarified that when a superconducting film is formed, excellent superconducting properties can be obtained in a superconducting thick film having a thickness of 0.5 μm or more and 30 μm or less.

Example 4 A cerium naphthenate dissolved in an ethanol solvent was applied to a sapphire single crystal substrate, and a heat treatment and an oxygen annealing treatment were performed to form a cerium oxide intermediate layer. The thickness of the intermediate layer is 1 μm
Met. On this intermediate layer, a superconducting seed film represented by the composition of YBa ₂ Cu ₃ O _7-d was formed by a laser ablation method. The thickness of the superconducting seed film was 1 μm.

On this superconducting seed film, Y was applied by a coating thermal decomposition method.
A superconducting thick film represented by the composition of Ba ₂ Cu ₃ O _7-d was formed. The starting material has a composition ratio of Y: Ba: Cu of 1: 2: 3.
A solution obtained by dissolving a naphthenate of each element in an ethanol solvent was prepared and subjected to coating, heat treatment, and oxygen annealing to form a superconducting thick film. The film thickness and critical current density of the superconducting film formed by the coating pyrolysis method were measured. Table 4 shows the relationship between the thickness of the superconducting film and the critical current density.

[0109]

[Table 4]

From the results in Table 4, it is found that after forming a predetermined intermediate layer by the coating thermal decomposition method, a superconducting seed film is formed by the laser ablation method, and a superconducting film is further formed thereon by the coating thermal decomposition method. It is clear that excellent superconducting characteristics can be obtained in a superconducting thick film having a thickness of 0.5 μm or more and 30 μm or less.

(Example 5) Lanthanum aluminate single crystal group
YBa on the plate using laser ablation method _TwoCu_Three
O_7-dA superconducting seed film represented by the following composition was formed. Super electric
The thickness of the conductive film was 1 μm.

Further, a superconducting thick film represented by the composition of YBa ₂ Cu ₃ O _7-d was formed on the superconducting seed film by a coating thermal decomposition method. The starting material has a composition ratio of Y: Ba: Cu of 1:
A solution in which naphthenates of each element were dissolved in an ethanol solvent so as to have a ratio of 2: 3 was prepared and subjected to coating, heat treatment and oxygen annealing to form a superconducting thick film. The thickness and critical current density of the formed superconducting film were measured. Table 5
2 shows the relationship between the thickness of the superconducting film formed by the coating pyrolysis method and the critical current density.

[0113]

[Table 5]

From the results shown in Table 5, it was found that a superconducting seed film was formed by a laser ablation method, and a superconducting film was formed thereon by a coating pyrolysis method to obtain a film having a thickness of 0.5 μm to 30 μm.
It has been clarified that excellent superconducting properties can be obtained with a superconducting thick film of μm or less.

The embodiments and examples disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

[0116]

As described above, the high-temperature superconducting thick film member according to one and other aspects of the present invention is particularly effective for obtaining the mass production effect of thin-film wires and large-area films. Suitable for wire rod repair technology. For example, even if a long wire is manufactured on a metal substrate, a portion having low characteristics is partially generated. However, if the present invention is used, a superconducting film can be formed in that portion, and the present invention is also effective for improving the rate-limiting step. It is.

For application to a current limiting device or the like, a large-area film is required. In general, the physical vapor deposition method has a small area on which a film can be formed at one time, and therefore, in order to obtain industrially low cost and uniform high characteristics, it is necessary to increase the vapor deposition area. The present invention is a method suitable for forming a large-area film by combining the swing and rotation of the substrate.

In the present invention, on a flexible metal substrate,
Alternatively, a wire or a large-area film formed on a single crystal, a polycrystal, or a metal substrate with an intermediate layer interposed therebetween is a preferable object. If a long current can be passed through a long wire on a flexible metal substrate, the impact on industrial applications such as cables and magnets will be very large. Also, the critical current density Jc under a magnetic field of 77K is significantly higher than that of a bismuth-based silver-coated wire rod, and even in an environment where the temperature is reduced to 77K or less by using supercooled nitrogen or cooling of a refrigerator. For example, the magnetic field characteristics are large, on the order of one order of magnitude, depending on the magnetic field strength, as compared with bismuth-based silver-coated wires. For this reason,
If mass production is possible as a practical material, cost merit will appear even if it exceeds the bismuth-based silver-coated superconducting wire by about one digit.

In addition, bismuth-based silver-coated wires can be applied to equipment that cannot be achieved. For example, an SN dislocation current limiter cannot be constructed with a bismuth-based silver-coated wire rod,
If large-scale yttrium-based films can be mass-produced at low cost and with high uniformity characteristics, it will be possible to disperse risks in the event of a system accident due to lightning strikes. In addition to the dramatic increase, the introduction of decentralized power sources can be effectively promoted.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing a configuration of a high-temperature superconducting thick film member according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view schematically showing another configuration of the high-temperature superconducting thick film member according to one embodiment of the present invention.

FIG. 3 is a cross-sectional view schematically showing still another configuration of the high-temperature superconducting thick film member according to one embodiment of the present invention.

FIG. 4 is a diagram illustrating a method of manufacturing a high-temperature superconducting thick film member according to one embodiment of the present invention.

FIG. 5 is a cross-sectional view for explaining a substrate inclined laser vapor deposition method.

FIG. 6 is a diagram for explaining a manufacturing method when the substrate is linear.

FIG. 7 is a perspective view showing a state in which the substrate is swung.

FIG. 8 is a perspective view showing how the substrate is rotated.

[Explanation of symbols]

1 Substrate, 2 intermediate layers, 3 superconducting thick films, 4 superconducting seed films, 5 high temperature superconducting thick film members.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Kazuya Omatsu 1-3-1 Shimaya, Konohana-ku, Osaka City F-term in Osaka Works, Sumitomo Electric Industries, Ltd. 5G321 AA01 AA04 BA01 BA03 CA18 CA22 CA24 CA27 CA28 DB22 DB44 DB55

Claims (27)

[Claims] 1. A substrate having a main surface and made of single crystal or polycrystal, and 0.1 μm or more and 3 μm formed on the main surface of the substrate.
m, a single-crystal intermediate layer having a thickness of 0.5 m or less, and 0.5 formed on the intermediate layer by a coating pyrolysis method.
A high-temperature superconducting thick-film member comprising: a single-crystal superconducting thick film having a thickness of not less than μm and not more than 30 μm. 2. The intermediate layer has a coefficient of thermal expansion closer to the coefficient of thermal expansion of the superconducting thick film than the coefficient of thermal expansion of the substrate, and the lattice of the superconducting thick film is larger than the lattice constant of the substrate. 2. The high-temperature superconducting thick film member according to claim 1, having a lattice constant close to a constant. 3. The method according to claim 1, wherein the intermediate layer and the superconducting thick film are
The high temperature superconducting thick film member according to claim 1, further comprising a single-crystal superconducting seed film. 4. The intermediate layer has a crystal structure obliquely inclined at an angle of 10 ° or less with respect to a main surface of the substrate, and has an in-plane orientation inclination angle of 30 ° or less. The high temperature superconducting thick film member according to any one of claims 1 to 3, wherein 5. The method according to claim 1, wherein the intermediate layer has a single-layer or multi-layer structure containing at least one oxide selected from the group consisting of zirconium, ytterbium, yttrium, and cerium. The high temperature superconducting thick film member according to any one of the above. 6. A substrate having a main surface and made of single crystal or polycrystal, a single-crystal superconducting seed film formed on the main surface of the substrate, and thermal decomposition applied to the superconducting seed film Formed by the method,
A high-temperature superconducting thick-film member comprising: a single-crystal superconducting thick film having a thickness of 0.5 μm or more and 30 μm or less. 7. The material of the superconducting seed film and the superconducting thick film has a REBCO123 structure and contains mutually different RE (rare earth) elements as constituent elements. 7. The high temperature superconducting thick film member according to 6. 8. The high temperature superconducting thick film member according to claim 7, wherein the melting point of the superconducting seed film is higher than the melting point of the superconducting thick film. 9. The material according to claim 1, wherein the material of the single crystal substrate includes at least one selected from the group consisting of sapphire, lanthanum aluminate, magnesium oxide and strontium titanate. A high-temperature superconducting thick-film member according to any of the above items. 10. The material of the polycrystalline substrate is a flexible metal containing at least one selected from the group consisting of stainless steel, Hastelloy, nickel, copper and aluminum, and having a thickness of 200 μm or less. The high-temperature superconducting thick film member according to any one of claims 1 to 8. 11. The superconducting thick film is made of REBCO.
The high temperature superconducting thick film member according to any one of claims 1 to 10, wherein the member has a 123 structure, and the RE (rare earth) element contains holmium. 12. A step of forming a monocrystalline intermediate layer having a thickness of 0.1 μm or more and 3 μm or less on a main surface of a substrate made of a single crystal or a polycrystal; Forming a single-crystal superconducting thick film having a thickness of not less than 30 μm or less using a coating pyrolysis method. 13. The method according to claim 1, further comprising, after forming the intermediate layer and before forming the superconducting thick film, forming a single-crystal superconducting seed film by physical vapor deposition.
A method for manufacturing a high-temperature superconducting thick film member according to claim 12. 14. The method for manufacturing a high temperature superconducting thick film member according to claim 12, wherein the intermediate layer is formed by a physical vapor deposition method. 15. The method according to claim 14, wherein the intermediate layer is formed by a laser ablation method in which a material is irradiated with a laser beam to deposit a substance scattered from the material on a main surface of the substrate. 3. The method for producing a high-temperature superconducting thick film member according to item 1. 16. The method according to claim 16, wherein the intermediate layer is formed by performing the laser ablation method in a state where a main surface of the substrate is inclined with respect to a surface of the raw material irradiated with the laser beam. A method for manufacturing a high-temperature superconducting thick film member according to claim 15. 17. The method according to claim 1, wherein the intermediate layer is formed by a coating thermal decomposition method alone, or is formed by laser annealing after being formed by a coating thermal decomposition method. 14. The method for producing a high-temperature superconducting thick film member according to 12 or 13. 18. The substrate has a linear shape, and one end of the substrate is wound around a first roll and the other end is wound around a second roll, so that the intermediate portion is formed on the substrate. The method for manufacturing a high-temperature superconducting thick-film member according to claim 12, wherein a layer and the superconducting thick film are sequentially formed. 19. The method according to claim 19, wherein the size of the substrate is 100 cm ² or more, and the substrate is formed by forming at least one of the intermediate layer and the superconducting thick film while swinging or rotating. Item 13. The method for producing a high-temperature superconducting thick film member according to item 12. 20. A step of forming a single-crystal superconducting seed film on a main surface of a single-crystal or polycrystalline substrate by physical vapor deposition; Forming a thick single-crystal superconducting thick film using a coating pyrolysis method. 21. The substrate having a linear shape, wherein one end of the substrate is wound around a first roll, and the other end is wound around a second roll, so that the superconducting film is formed on the substrate. 21. The method for manufacturing a high-temperature superconducting thick film member according to claim 20, wherein the seed film and the superconducting thick film are sequentially formed. 22. The size of the substrate is 100 cm ² or more, and the substrate is formed by forming at least one of the superconducting seed film and the superconducting thick film while swinging or rotating. A method for manufacturing a high-temperature superconducting thick film member according to claim 20. 23. The step of forming the single-crystal superconducting thick film using a coating pyrolysis method includes forming a superconducting thick film by the coating pyrolysis method and then performing single crystallization by a laser annealing method. The method for producing a high-temperature superconducting thick film member according to claim 12, wherein the method is characterized in that: 24. An annealing source in the laser annealing method, wherein an excimer laser having a wavelength of 0.1 μm to 0.5 μm or a YAG laser having a wavelength of 0.5 μm to 2 μm is provided.
A method for manufacturing a high temperature superconducting thick film member according to claim 23. 25. The high-temperature superconducting thick film according to claim 12, wherein the superconducting thick film is subjected to at least four treatments of temporary sintering, final finishing, post annealing and oxygen annealing. A method for manufacturing a membrane member. 26. The raw material in the coating pyrolysis method includes an organic metal raw material.
0. The method for producing a high-temperature superconducting thick film member according to 0. 27. The method for manufacturing a high-temperature superconducting thick film member according to claim 12, wherein the superconducting thick film is formed on both surfaces of the substrate.