MX2008009908A - Process for producing superconducting thin-film material, superconducting equipment and superconducting thin-film material - Google Patents

Abstract

A process for producing a superconducting thin-film material, including the vapor phase step of forming superconducting layer (3) in accordance with a vapor phase method and the liquid phase step of forming superconducting layer (4) abutting on the superconducting layer (3) in accordance with a liquid phase method. Preferably, the process further includes the step of forming interlayer (2) between the superconducting layer (3) and metal substratum (1). It is preferred that the metal substratum (1) consist of a metal, and that the interlayer (2) consist of an oxide with any of rock, perovskite and pyrochlore crystal structures, and that both the superconducting layer (3) and the superconducting layer (4) have an RE123 composition. Accordingly, the value of critical current can be enhanced.

Description

PROCEDURE FOR PRODUCING SUPERCONDUCTOR THIN FILM MATERIAL, SUPERCONDUCTOR EQUIPMENT AND SUPERCONDUCTOR STRAIGHT FILM MATERIAL FIELD OF THE INVENTION The present invention relates to a method for manufacturing a superconducting thin film material, a superconducting device and a superconducting thin film material. More specifically, the invention relates to a method of manufacturing a superconducting thin film material having a RE123 composition, a superconducting device and a superconducting thin film material.

BACKGROUND OF THE INVENTION Two types of superconducting cables have now been developed in particular: a superconducting cable using a superconductor based on bismuth and a superconducting cable using a superconductor based on RE123. Of these cables, the superconducting cable based on RE123 has the advantage that the critical current density at liquid nitrogen temperature (77.3 K) is greater than that of the superconducting cable based on bismuth. In addition, it has the advantage of a high critical current value under a low temperature condition and under a certain magnetic field condition. For the REF. : 195033 Therefore, the superconducting cable based on RE123 is expected to be the next generation high temperature superconductor cable. Unlike the superconductor based on bismuth, the superconductor based on RE123 can not be covered with a jet of silver. Therefore, the superconductor based on RE123 is manufactured by depositing a superconductor film (superconducting thin film material) on a textured metal substrate by a vapor phase method only or a liquid phase method only. Japanese Patent Laid-Open No. 2003-323822 (Patent Document 1), for example, discloses a method for manufacturing a superconducting thin film material based on conventional RE123. Patent document 1 describes the technique of forming an intermediate layer on a metal tape substrate using the pulse laser deposition (PLD) method, forming a first superconducting layer having a composition RE123 on the intermediate layer using the PLD method and forming a second superconducting layer having a composition RE123 on the first superconducting layer using the laser spot deposition method. Patent Document 1: Japanese Patent open to the public No. 2003-323822 BRIEF DESCRIPTION OF THE INVENTION In order to increase the critical current value of the superconducting cable, the thickness of the superconducting thin film material can be increased to increase the cross-sectional area where the current flows. However, conventional superconducting cable has the following property. As the thickness of the superconducting thin film material increases, the critical current density decreases and the critical current value gradually becomes slower to increase. The resulting problem therefore is that the critical current density and the critical current value can not be improved. Another problem is that the method of depositing the superconducting thin film material onto the textured metal substrate using only the liquid phase method prevents crystal growth of the superconducting thin film material. An object of the present invention therefore is to provide a method for manufacturing a superconducting thin film material, a superconducting device and a superconducting thin film material for which the critical current density and the critical current value can be improved. Another object of the present invention is providing a method for manufacturing a superconducting thin film material, a superconducting device and a superconducting thin film material for which glass growth of the superconducting thin film material is facilitated. A method of manufacturing a superconducting thin film material according to one aspect of the present invention includes: a vapor phase step of forming a superconducting vapor phase growth layer by a vapor phase method; and a liquid phase step of forming a superconducting liquid phase growth layer by a liquid phase method so that the superconducting liquid phase growth layer is in contact with the superconductive vapor phase growth layer. A method of manufacturing a superconducting thin film material according to another aspect of the present invention includes: n stages in the vapor phase (n is an integer of at least 2), each to form a superconducting growth layer in vapor phase by a vapor phase method; and n stages in liquid phase, each to form a superconducting layer of liquid phase growth by a liquid phase method. In a first stage in the vapor phase of the n stages in the vapor phase, a first superconductive layer of growth is formed in the vapor phase.

In a first stage in the liquid phase of the n stages in the liquid phase, a first superconducting layer of liquid phase growth is formed so that the first superconducting layer of liquid phase growth is in contact with the first superconducting layer of phase growth. steam. In a k th step in the vapor phase (k is an integer that satisfies the inequality n> k > 2) of the n stages in the vapor phase, the k th superconductive layer of growth in the vapor phase is formed of so that the k th superconductive layer of growth in vapor phase is in contact with a (k-1) -th superconductive layer of growth in liquid phase. In a k th stage in the liquid phase of the n stages in the liquid phase, the k th superconducting layer of liquid phase growth is formed so that the k th superconducting layer of liquid phase growth is in contact with the k th superconducting layer of growth in vapor phase. The inventors of the present application found that the uniformity of the surface of the superconducting thin film material as well as the compactness of the glass of the superconducting thin film material are important factors to avoid the decrease of the critical current density due to an increase in the thickness of film. Regarding the vapor phase method, as the thickness of a film increases as it is produced, the temperature of the surface where the film is formed decreases resulting in a phenomenon that the number of particles oriented on the a-axis is relatively larger. Therefore, a conventional superconducting thin film material formed by only the vapor phase method has its surface uniformity which deteriorates as the film thickness increases. With respect to the liquid phase method, as the thickness of a film as it is produced increases (particularly a thickness exceeding 1 μp?), The compactness of the glass of the superconducting thin film material deteriorates. Therefore, there is a conventional case where the desired critical current density and the desired critical current value can not be obtained even if the thickness of the superconducting thin film material is increased. Therefore, according to the method of manufacturing a superconducting thin film material of the present invention, a superconductive vapor phase growth layer is formed by a vapor phase method and a superconducting phase growth layer is formed. liquid by a liquid phase method so that the liquid phase superconductor layer is in contact with the superconducting vapor phase growth layer. In this way, in the process of forming the superconducting layer of growth in liquid phase, the liquid it fills the irregular surface of the superconductive layer of growth in the vapor phase and the growth of the crystal of the superconducting layer of liquid phase growth occurs in a seed which is the surface of the superconductive layer of growth in the vapor phase. Therefore, the irregularity of the surface of the superconductive layer of growth in vapor phase becomes uniform. In addition, since the superconducting thin film material consists of both a superconducting vapor phase growth layer and a superconducting liquid phase growth layer, each of the superconductive vapor phase growth layer and the superconducting layer of the vapor phase. Liquid phase growth can be made thinner compared to the case where the superconducting thin film material is composed of only one of the superconducting vapor phase growth layer and the superconducting liquid phase growth layer. In this way the irregularity of the surface of the superconducting thin film material is uniform and the deterioration of the compactness of the glass of the superconducting thin film material can be prevented. As a result, the thickness of the superconducting thin film material can be increased while the uniformity of the surface of the superconducting thin film material and the compactness of the superconducting thin film material crystal are excellent Therefore, to avoid a decrease in the critical current density due to an increased film thickness and the critical current density and the critical current value can be improved. In the initial stage of the growth of the liquid phase growth superconductive layer by the liquid phase method, a layer that serves as a seed of the crystal growth is necessary. Regarding the conventional method of depositing a superconducting thin film material using only the liquid phase method, there is no layer that serves as a seed of crystal growth, which means that somehow crystal growth is prevented. In contrast, with respect to the manufacturing method of the present invention, the superconductive vapor phase growth layer serves as a crystal growth seed which facilitates crystal growth of the superconducting thin film material. Further, with respect to the method of manufacturing the superconducting thin film material in the other aspect mentioned before the present invention, the superconducting thin film material is made by alternately performing the step of forming a superconducting layer of growth in the phase of steam and the stage of forming a superconducting layer of liquid phase growth and when carrying out each stage multiple times. Therefore, the total thickness of the superconducting layer can be increased while each of the superconducting vapor phase growth layer and each of the superconducting liquid phase growth layer remain thin. In this way, the critical current value can be increased further. According to the method of manufacturing a superconducting thin film material in an aspect of the present invention mentioned above, preferably the superconductive vapor phase growth layer is formed on a front surface side of a substrate in the phased stage steam. The method includes: a step in the vapor phase of the rear surface side of forming a superconducting vapor phase growth layer on the rear surface side by a vapor phase method on the rear surface side of the substrate; and a liquid phase stage on the rear surface side of forming the superconducting liquid phase growth layer on the rear surface side of the superconducting layer by a liquid phase method so that the growth of the liquid phase on the side of the rear surface of the superconducting layer is in contact with the vapor phase growth of the rear surface side of the superconducting layer.

In this way, the respective superconducting thin film materials can be formed on both sides of the substrate and in this way the number of current paths of the superconducting cable can be increased and the critical current density and the critical current value can be further improved. . It should be noted that a "front surface of the substrate" and a "rear surface of the substrate" are simply used to differentiate two major surfaces of the substrate from each other and the front surface can be either of the two major surfaces. According to the method of manufacturing a superconducting thin film material in an aspect mentioned before the present invention, preferably the superconductive vapor phase growth layer is formed on the side of the front surface of a substrate in the stage in vapor phase. The method further includes the step of forming an intermediate layer between the superconductive vapor phase growth layer and the substrate. The substrate is made of a metal, the intermediate layer is made of an oxide that has a crystalline structure of a type of rock, of the perovskite and pyrochlore type, and the superconductive layer of growth in vapor phase and the superconductive layer of liquid phase growth each have a RE123 composition.

According to the method of manufacturing a superconducting thin film material in another aspect of the present invention mentioned above, a first superconductive vapor phase growth layer is preferably formed on a front surface side of a substrate in a first stage in the vapor phase. The method further includes the step of forming an intermediate layer between the first superconductive vapor phase growth layer and the substrate. The substrate is made of a metal, whose intermediate layer is made of an oxide that has a crystalline structure of a type of rock, perovskite type and pyrochlore type, and the first to the nth superconducting layer of growth in vapor phase and the first to the nth superconductive layers of growth in liquid phase each have a composition RE123. In this way an excellent superconducting thin film material can be obtained in crystal orientation and surface uniformity and the critical current density and the critical current value can be improved. According to the method of manufacturing a superconducting thin film material in an aspect mentioned before the present invention, preferably the method further includes the step of forming a superconducting layer after the liquid phase stage so that the superconducting layer is in contact with the layer superconductor of growth in liquid phase. According to a method for manufacturing a superconducting thin film material in the other aspect mentioned before the present invention, preferably the method further includes the step of forming a superconducting layer after the nth stage in liquid phase so that the superconductive layer is in contact with the nth superconducting liquid phase growth layer. The superconducting layer that is grown by the liquid phase method is superior in surface uniformity with respect to the superconducting layer that grows by the vapor phase method. Therefore, the superconducting layer can be formed on the superconducting layer which is excellent in surface uniformity. According to the manufacturing method as described above, preferably the vapor phase method is any of the laser deposition method, electrostatic deposition method and electron beam evaporation method. According to the manufacturing method as described above, the liquid phase method is a method of organic metal deposition (MOD). Therefore, excellent superconducting thin film material can be obtained in crystal orientation and surface uniformity and the critical current density can be improved and the critical current value. A superconducting device according to the present invention utilizes a superconducting thin film material made by the method of manufacturing a superconducting thin film material, as described above. With the superconducting device of the present invention, the critical current density and the critical current value can be improved. A superconducting thin film material of the present invention includes a first superconducting layer and a second superconductive layer formed to be in contact with the first superconducting layer and has a critical current value greater than 110 (A / cm width). It should be noted that the term "RE123" herein refers to RExBayCuz07-d wherein 0.7 < x < 1.3, 1.7 < and < 2.3, 2.7 < z = 3.3. RE of "RE123" refers to the material that includes at least any of the rare earth elements and an yttrium element. The rare earth element includes, for example, neodymium (Nd), gadolinium (Gd), holmium (Ho) and samarium (Sm). With a method of manufacturing a superconducting thin film material, a superconducting device and a superconducting thin film material of the present invention, the current density can be improved criticism and the critical current value.

BRIEF DESCRIPTION OF THE FIGURES Figure 1 is a perspective view in partial cross-section showing schematically a structure of a superconducting thin film material in a first embodiment of the present invention. Fig. 2 is a flowchart showing a method of manufacturing the superconducting thin film material in the first embodiment of the present invention. Figures 3a-3b show schematically the manner in which the superconducting layer is formed in the first embodiment of the present invention. Figure 4 is a perspective view in partial cross-section showing schematically a structure of another superconducting thin film material in a first embodiment of the present invention. Figure 5 is a perspective view in partial cross-section showing schematically a structure of a superconducting thin film material in a second embodiment of the present invention. Fig. 6 is a flow chart showing a method of manufacturing the superconducting thin film material in the second embodiment of the present invention Figure 7 is a perspective view in partial cross-section showing schematically a structure of a superconducting thin film material in a third embodiment of the present invention. Figure 8 is a flow diagram showing a method of manufacturing the superconducting thin film material in the third embodiment of the present invention. Figure 9 shows a relation between the thickness of a superconducting layer and a critical current value Ic the example 1 of the present invention. Figure 10 shows a relationship between the thickness of a superconducting layer and the surface roughness Ra in Example 1 of the present invention.

BRIEF DESCRIPTION OF THE REFERENCE NUMBERS 1 metal substrate, the front surface, Ib rear surface, 2 intermediate layer, 3-9 superconductor layer, 10 superconducting thin film material DETAILED DESCRIPTION OF THE INVENTION In the following the modalities of the present invention will be described based on the figures.

First embodiment Figure 1 is a perspective view in partial cross-section showing schematically a structure of a superconducting thin film material in a first embodiment of the present invention. With reference to Figure 1, the superconducting thin film material 10 in the present embodiment is tape-shaped and includes a metal substrate 1, an intermediate layer 2, a superconducting layer 3 which is a superconducting vapor phase growth layer (first superconducting layer) and a superconducting layer 4 which is a liquid phase growth superconducting layer (second superconducting layer). The superconducting thin film material 10 is used for devices such as, for example, the superconducting device. The metal substrate 1 is made of a metal such as stainless steel, nickel alloy (Hastelloy, for example) or, for example, a silver alloy. The intermediate layer 2 is formed on a front surface of a metal substrate 1 and functions as a layer that prevents diffusion. The intermediate layer 2 is made of an oxide having a crystal structure which is any type of rock, perovskite type and pyrochlore type, for example. Specifically, the intermediate layer 2 is made of a material such as ceric oxide, stabilized zirconia with yttria (YSZ), magnesium oxide, yttrium oxide, ytterbium oxide and zirconia barium, for example. The superconducting layer 3 and the superconducting layer 4 are layered on the intermediate layer 2. The superconducting layer 3 and the superconducting layer 4 is made substantially of the same material and have a composition RE123, for example. Although the structure includes in the intermediate layer 2 it is described in relation to figure 1, intermediate layer 2 may not be included. A method of manufacturing a superconducting thin film material in the present embodiment will now be described. Figure 2 is a flow chart showing the method of making the superconducting thin film material in the first embodiment of the present invention. With reference to Figures 1 and 2, according to the manufacturing method, the superconducting thin film material in the present embodiment, the metal substrate 1 is prepared first (stage SI), the intermediate layer 2 made of YSZ, by For example, the metal substrate 1 is formed on the front surface by the laser deposition method (step S2). Then, on the intermediate layer 2, the superconducting layer 3 having a composition RE123, for example, is formed by the vapor phase method (step S3).

As the vapor phase method for forming the superconducting layer 3, for example the laser deposition method, the electrostatic deposition method or the electron beam evaporation method is used. Subsequently, the superconducting layer 4 having a composition RE123, for example, is formed by a liquid phase method such as the MOD method so that the superconducting layer 4 is in contact with the superconducting layer 3 (step S4). Through the steps described in the above, the superconducting thin film material 10 is completed. In case where intermediate layer 2 is not included, the intermediate layer 2 formation step (step S2) as described above is not performed. Instead, in the step of forming the superconducting layer 3 (step S3), the superconducting layer 3 is shaped to be in contact with the front surface of the metal substrate 1. Figures 3a-3b schematically show a manner in which the superconducting layer is formed in the first embodiment of the present invention. With reference to Figure 3 (a) according to the superconducting thin film material 10 and the method of manufacturing thereof in the present embodiment, the superconducting layer 3 is formed by the vapor phase method. Therefore, if the film thickness of the superconducting layer 3 is large, in some cases the surface SI of the superconducting layer is irregular. However, with reference to Figure 3 (b), in the method of forming the superconducting layer 4 by the liquid phase method, the solution containing the components of the superconducting layer 4 fills the irregular surface and the crystal growth of the superconducting layer 4 on the seed in which the SI surface of the superconducting layer 3 is. In this way a uniformed surface S2 is obtained. With reference to Figure 3 (a) and Figure 3 (b), the sum of the film thickness di of the superconducting layer 3 and the thickness d2 of the film of the superconducting layer 4 is the thickness d3 of the film material. thin superconductor. Therefore, the film thickness d3 of the superconducting thin film material can become large without greatly increasing the film thickness of the superconducting layer 3 and the film thickness d2 of the superconducting layer 4. In this way the uniformity of the SI surface of the superconducting layer 3 can be maintained and the compactness of the crystal of the superconducting layer 4 can be prevented from deteriorating. As a result, in the state where the uniformity of the surface S2 of the superconducting thin film material as well as the compactness of the glass of the superconducting thin film material are satisfactory, the thickness of the superconducting thin film material can be increased. Therefore, a decrease in the density of critical current due to an increase in the film thickness and the critical current density and the critical current value can be improved. In addition, in the method of forming the superconducting layer 4 by the liquid phase method, the superconducting layer 3 serves as the seed of crystal growth. Therefore, crystal growth of the superconducting thin film material is facilitated. The intermediate layer 2 made of an oxide having a crystal structure which is any of the rock type, perovskite type and pyrochlore type is formed between the superconducting layer 3 and the metal substrate 1 and the superconducting layer 3 and the superconducting layer 4 they both have a RE123 composition. Therefore, the superconducting thin film material has excellent surface uniformity and excellent glass compaction can be obtained and the critical current density and the critical current value can be improved. Since the vapor phase method is any of the laser deposition method, the electrostatic deposition method and the electron beam evaporation method, a superconducting thin film material having an excellent surface uniformity and a compact condition can be obtained. of excellent glass and can improve the critical current density and the value of critical current. Since the liquid phase method is the MOD method, a superconducting thin film material having excellent surface uniformity and excellent crystal compaction can be obtained and the critical current density and critical current value can be improved. In the present embodiment, in the case where it is illustrated where the uppermost layer between the layers constituting the superconducting thin film material is the superconducting layer 4. As shown in Figure 4, another superconducting layer 9 can be formed to be in contact with the superconducting layer 4 after the superconducting layer 4 is formed (step S4). This superconducting layer 9 can be formed by a vapor phase method or can be formed by a liquid phase method. Accordingly, on the superconducting layer 4 having excellent surface uniformity, another superconducting layer 9 is formed so that the superconducting thin film material can be thickened. Second Modality Figure 5 is a perspective view in partial cross-section showing schematically a structure of a superconducting thin film material in a second embodiment of the present invention. With Referring to Fig. 5, the superconducting thin film material 10 in the present embodiment includes a metal substrate 1, an intermediate layer 2, a superconducting layer 3 which is a first superconducting vapor phase growth layer and a superconducting layer 4. superconductor which is a first superconducting layer of liquid phase growth and additionally includes a superconducting layer 5 which is a second superconductive layer of vapor phase growth and a superconducting layer 6 which is a second superconducting layer in liquid phase. The superconducting layer 5 and the superconducting layer 6 are laminated onto the superconducting layer 4. The superconducting layer 5 and the superconducting layer 6 are made substantially of the same material and have a composition, for example, of RE123. A method of manufacturing a superconducting thin film material in the present embodiment is now described. Figure 6 is a flow diagram showing the method of manufacturing the superconducting thin film material in the second embodiment of the present invention. With reference to Figures 5 and 6, according to the method of manufacturing the superconducting thin film material in the present embodiment, after the superconducting layer 4 is formed (step S4), the layer 5 The superconductor having, for example, a composition RE123 is formed by a vapor phase method so that the superconducting layer 5 is in contact with the superconducting layer 4 (step S5). The vapor phase method used to form the superconducting layer 5 is, for example, the laser deposition method, the electrostatic deposition method or the electron beam evaporation method. Subsequently, the superconducting layer 6 having a composition RE123, for example, is formed by the liquid phase method such as MOD so that the superconducting layer 6 is in contact with the superconducting layer 5 (step S6). Through the steps described in the above, the superconducting thin film material 10 is completed. Any other characteristic in addition to those described above of the superconducting thin film material 10 and the manufacturing method thereof are similar to those of the superconducting thin film material and the method of manufacturing same in the first embodiment, as shown in FIG. Figures 1 and 2. Therefore, similar components are indicated with similar reference numbers and their description will not be repeated. With respect to the superconducting thin film material 10 and the method of manufacturing thereof in the present embodiment, the effects similar to the effects of the superconducting thin film material and the method of making it in the first mode can be obtained. In addition, the formation of the superconducting layer by the vapor phase method and the formation of the superconducting layer by the liquid phase method are performed alternately and each is performed twice to manufacture the superconducting thin film material. Therefore, the thickness of the superconducting thin film material can be increased while the thickness of each of the superconductive layers 3 to 6 is kept thin. Accordingly, the critical current value can be further increased. In relation to the present embodiment, the case in which two stages in the vapor phase of formation of the superconductive layers of growth in respective vapor phase by the vapor phase method and two stages of liquid phase are alternately performed is illustrated. of formation of the respective liquid phase growth superconducting layers by the liquid phase method. Alternatively, the formation of the superconductive layer by the vapor phase method and the formation of the superconducting layer by the liquid phase method can be carried out alternately and each can be carried out twice or more. With respect to the present embodiment, the case is illustrated where the superconducting layer 6 is the most between the layers that make up the superconducting thin film material. Alternatively, after the superconducting layer 6 forms (step S6), another additional superconductive layer can be formed to be in contact with the superconducting layer 6. This superconducting layer can be formed by a vapor phase method or it can be formed by a liquid phase method. In this way, on the superconducting layer 6 having excellent surface uniformity, another superconductive layer can be formed to increase the thickness of the superconducting thin film material. Third Mode Figure 7 is a perspective view in partial cross-section showing schematically the structure of a superconducting thin film material in a third embodiment of the present invention. With reference to Figure 7, the superconducting thin film material 10 in the present embodiment further includes a superconducting layer 7 which is a superconducting vapor phase growth layer of the rear surface side and the superconducting layer 8 which is the superconductive liquid phase growth layer on the rear surface side. The superconducting layer 7 and the superconducting layer 8 are laminated together on the rear surface side Ib of a metal substrate 1. Layer 7 The superconductor and the superconducting layer 8 are made substantially of the same material and have a composition, for example RE123. A method of manufacturing the superconducting thin film material in the present embodiment will now be described. Figure 8 is a flow diagram illustrating a method of manufacturing the superconducting thin film material in the third embodiment of the present invention. With reference to Figure 7 and Figure 8, according to the method of manufacturing the superconducting thin film material in the present embodiment, after the superconducting layer 6 is formed (step S6), the superconducting layer 7 is formed which has a composition RE123, for example, by the vapor phase method to be in contact with the back surface Ib of the metal substrate 1 (step S7). The vapor phase method used to form the superconducting layer 7 is, for example, the laser deposition method, the electrostatic deposition method or the electron beam evaporation method. Subsequently, the superconducting layer 8 having a composition RE123, for example, is formed by a liquid phase method such as the MOD method to be in contact with the superconducting layer 7 (step S8). Through the stages described in the above, the thin film material 10 is completed superconductor With respect to the superconducting thin film material 10 and the method of manufacturing thereof in the present embodiment, effects similar to the effects of the superconducting thin film material and the method of manufacturing thereof in the first embodiment can be obtained. Furthermore, since the respective superconducting thin film materials can be formed on both the front surface side and the rear surface side Ib of the metal substrate 1, the number of current paths of the superconducting cable can be increased and can be increased. improve the critical current density and the critical current value additionally. The synchronization in which the successive steps of forming the superconducting layer 7 (step S7) and forming the superconducting layer 8 (step S8) are performed can be any synchronization. For example, these steps can be carried out immediately after the metal substrate 1 is prepared (step SI) or immediately after the superconducting layer 3 is formed (step S2). In addition, an intermediate layer can be formed between the metal substrate 1 and the superconducting layer 7. In relation to the first to third embodiments, the case in which a superconducting layer made of a material having a composition RE123 is formed is illustrated. However, the present invention in this case is not limited and is also applicable to a method of manufacturing a superconducting layer of another material such as, for example, a material based on bismuth. Furthermore, in relation to the first to third embodiments, the case is illustrated in which the intermediate layer 2 is formed on the surface of the front of the metal substrate 1. However, intermediate layer 2 is not formed. In this case, the superconducting layer 3 is formed to be in contact with the metal substrate 1. EXAMPLE 1 In this example, each of the respective superconducting thin film materials is made for the comparative example A, example B of the present invention, example C of the present invention, comparative example D and comparative example E, and The critical current value and the surface uniformity are measured. Comparative Example A: an intermediate layer made of a metal oxide is formed on a Ni alloy substrate using the vapor phase deposition method. The surface roughness Ra of the surface of the intermediate layer is 5 nm. Subsequently, a superconducting layer made of HoBa2Cu30x (HoBCO) is formed on the intermediate layer at a thickness of 0.2 μm using the PLD method. Example B of the present invention: first a structure similar to that of comparative example A is produced. Subsequently, a superconducting layer made of HoBa2Cu3Ox (HoBCO) up to a thickness of 0.3 μ is formed on the superconductor layer. using the MOD method. In this way, the total thickness of the superconducting layer is 0.5 μt ?. Example C of the present invention: firstly, produces a structure similar to that of Example B of the present invention. Subsequently, an elaborated superconducting layer of HoBa2Cu30x (HoBCO) is formed on the superconductor layer at a thickness of 0.3 μ? T? using the PLD method. In this way, the total thickness of the superconducting layer is 0.8 μ ?. Comparative Example D: first a structure similar to that of Comparative Example A is produced. Subsequently, an elaborated superconducting layer of HoBa2Cu30x (HoBCO) is formed on the superconductor layer to a thickness of 0.3 μp? using the PLD method. In this way, the total thickness of the superconducting layer is 0.5 μp ?. Comparative example E: a structure similar to that of comparative example D is produced. Subsequently, a superconducting layer made of HoBa2Cu30x (HoBCO) up to a thickness of 0.3 is formed on the superconductor layer. using the PLD method. In this way, the total thickness of the superconducting layer is 0.8 μ ??. The critical current value of width per cm and the surface roughness Ra, measured for each of the comparative example A, example B of the present invention, example C of the present invention, comparative example D and comparative example E are shown in FIG. Table 1 and Figures 9 and 10. Surface roughness Ra means the arithmetic mean of roughness Ra defined by JIS (Japanese industrial standards).

Table 1 fifteen With reference to table 1 and figures 9 and 10, as seen from a comparison between comparative example A, example B of the present invention and example C of the present invention, the critical current value is higher as it is larger the thickness of the superconducting layer. As also seen from a comparison between the comparative example A, the comparative example D and the comparative example E, the critical current value is also larger as the thickness of the superconducting layer is greater. This is the reason why the cross-sectional area when the current flow increases as the thickness of the superconducting layer increases. As seen in a comparison between Example B of the present invention and Comparative Example D, regardless of the fact that Example B of the present invention and Comparative Example D have the same thickness, Example B of the present invention it has a lower surface roughness Ra and a higher critical current value. As also seen from a comparison between example C of the present invention and comparative example E, regardless of the fact that example C of the present invention and comparative example E have the same thickness, example C of this The invention has a surface rugosity Ra less and a higher critical current value. It is observed from the above that the uniformity of the surface of the layer The superconductor can improve and the critical current density and the critical current value can be improved by forming the superconducting layer by the liquid phase method after forming the superconducting layer by a vapor phase method, according to the examples of the present invention. It should be considered that the modalities described in the above are in all aspects as an illustration and not by way of limitation. It is intended that the scope of the present invention be defined by the claims and not by the above embodiments and examples, and includes all modifications and equivalent variations in the meaning and scope of the claims.

INDUSTRIAL APPLICABILITY The present invention is suitable for a superconducting device including, for example, a superconductor fault current limiter, a magnetic field generating device, a superconducting cable, a superconducting common link and a superconducting coil and the like. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (8)

CLAIMS Having described the invention as above, the content of the following claims is claimed as property:

1. A method of manufacturing a superconducting thin film material, characterized in that it comprises: a step in the vapor phase of forming a superconductive layer of growth in the vapor phase, by a vapor phase method; and a liquid phase stage for forming a liquid phase growth superconducting layer by a liquid phase method so that the superconducting liquid phase growth layer is in contact with the superconductive vapor phase growth layer. The method of manufacturing a superconducting thin film material according to claim 1, characterized in that: the superconductive vapor phase growth layer is formed on a front surface side of a substrate in the vapor phase stage and the method further comprises: a stage in the vapor phase on the side of the rear surface forming a superconductive layer of vapor phase growth on the side of the rear surface by a vapor phase method on one side at the rear surface of the substrate; and a liquid phase stage on the rear surface side of forming a liquid phase growth superconducting layer on the rear surface side by a liquid phase method so that the superconducting liquid phase growth layer on the surface side back is in contact with the superconducting vapor phase growth layer on the side of the rear surface. 3. The method of manufacturing the superconducting thin film material according to claim 1, characterized in that it further comprises the step of forming a superconducting layer after the stage in liquid phase so that the superconducting layer is in contact with the superconductor layer of growth in liquid phase. 4. A superconducting device, characterized in that it uses a superconducting thin film material manufactured by the method of manufacturing a superconducting thin film material, in accordance with claim 1. 5. The method of manufacturing a superconducting thin film material, characterized because comprises: n stages in vapor phase (n is an integer of at least 2), each to form a superconducting vapor phase growth layer by a vapor phase method; and n stages in the liquid phase, each to form a superconducting layer of liquid phase growth by a liquid phase method, wherein in a first phase in the vapor phase of n stages in the vapor phase, a first superconducting layer of the liquid phase is formed. growth in the vapor phase, in a first stage in the liquid phase of the n stages in the liquid phase, a first superconductive layer of growth is formed in the liquid phase so that the first superconducting layer of liquid phase growth is in contact with the first superconductive layer of growth in vapor phase, in the k th stage in vapor phase (k is an integer that satisfies the inequality n> k> 2) of n stages in vapor phase, a k th layer is formed superconductor of growth in vapor phase so that the k th superconducting layer of growth in vapor phase is in contact with a (k-1) -th superconductive layer of growth in liquid phase, and in a th stage in liquid phase of the n stages in liquid phase, the kth superconductive layer of growth in liquid phase is formed so that the kth superconductive layer of growth in liquid phase is in contact with the kth superconducting layer of growth in vapor phase. 6. The method of manufacturing superconducting thin film material according to claim 5, characterized in that it further comprises the step of forming a superconducting layer after the nth stage in liquid phase so that the superconductive layer is in contact with the n th superconductive layer of growth in liquid phase. 7. A superconducting device, characterized in that it uses a superconducting thin film material manufactured by the method of manufacturing superconducting thin film material according to claim 5. 8. A superconducting thin film material, characterized in that it comps a first superconducting layer and a second superconducting layer. which are formed to be in contact with the first superconducting layer and which has a critical current value greater than 110 (A / cm width).