JP2010003435A - Superconducting wire rod and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a superconducting wire rod made by connecting superconducting wire rods with a superconductor, and to provide a method for manufacturing the same. <P>SOLUTION: The superconducting wire rod includes a first superconducting wire having a first superconducting layer with a main surface of a c-axis surface, a second superconducting wire which is juxtaposed to the first superconducting wire and has a second superconducting layer with a main surface of the c-axis surface, and a superconducting connector made of a superconductor which is connected to the main surface of the first superconducting layer and that of the second superconducting layer to electrically connect the first superconducting layer to the second superconducting layer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a superconducting wire, and more particularly to a superconducting wire in which superconducting wires are connected to each other and a method for manufacturing the same.

The development of superconducting applications such as superconducting coils, superconducting magnets, MRI devices, magnetic levitation trains, superconducting energy storage devices (SMES) is highly expected.
In particular, high-critical current oxide superconducting materials that have recently been put into practical use are expected to be usefully applied to fusion reactors, magnetic levitation trains, accelerators, magnetic diagnostic equipment (MRI), and some of them are already in practical use. Has been made.

  In order to further develop superconductivity, it is important to develop superconducting connection technology. That is, there is a need for a superconducting connection capable of realizing a superconducting permanent current mode, rather than simply connecting the superconductors with a low resistance normal conductor.

  Currently, the length of the superconducting wire is being increased, but in the manufacture of the wire, the shorter the wire, the easier it is to manufacture. After manufacturing a relatively short superconducting wire, the superconducting connection is made to the desired length. If possible, a long superconducting wire can be stably obtained.

Furthermore, in order to realize the permanent current mode necessary for high-performance NMR, a superconducting wire having a resistance value of 1.0 × 10 ⁻¹² Ω or less is required. For example, the superconducting wire is a normal current such as silver. In the conventional superconducting connection technology that connects with a conductor, the resistance value is in the order of 1.0 × 10 ⁻⁹ Ω (for example, Non-Patent Document 1).

In addition, the technique regarding the semiconductor element using a superconducting material is mentioned in connection with the technique which connects superconducting materials. In this technique, a superconducting film of biaxial orientation is formed on a superconducting material of biaxial orientation and superconducting connection is performed. This is a technique in the case where the film is formed on the same single crystal substrate. For example, it cannot be applied to connection of a superconducting wire using a superconducting layer provided on a different metal tape. Moreover, in a semiconductor element using a superconducting material, there is a possibility that a current of about 1 A at the maximum can be passed, but a current of at least 5 A cannot be passed. As described above, conventional techniques relating to semiconductor elements using a superconducting material cannot be applied to superconducting wires used in superconducting coils, superconducting magnets, MRI apparatuses, magnetic levitation trains, SMES, and the like.
Journal of Physics: Conference Series VOL.43 (2006), ppp.166-169, 7th European Conference on Applied Superconductivity, “Low resistance of the YBCO coated conductor” by J. Kato-Yoshioka, N. Sakai, S. Tajima, S.Miyata, T.Watanabe, Y.Yamada, N.Chikumoto, K.Nakao, T.Izumi and Y.Shiohara.

  The present invention provides a superconducting wire in which superconducting wires are connected by a superconductor, and a method for manufacturing the same.

  According to one aspect of the present invention, a first superconducting wire having a first superconducting layer having a c-axis surface as a main surface and a second superconducting layer juxtaposed with the first superconductor and having a c-axis surface as a main surface. Are connected to the second superconducting wire, the main surface of the first superconducting layer, and the main surface of the second superconducting layer, respectively, and electrically connecting the first superconducting layer and the second superconducting layer. There is provided a superconducting wire characterized by comprising a superconducting connection body made of a superconductor to be connected.

  According to another aspect of the present invention, the main surface of the first superconducting wire having the first superconducting layer having the c-axis surface as a main surface and the second superconducting layer having the c-axis surface as a main surface are provided. A superconducting connection body made of a superconductor that electrically connects the first superconducting wire and the second superconducting wire is formed on the main surface of the second superconducting wire. A manufacturing method is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the superconducting wire which connected the superconducting wire with the superconductor, and its manufacturing method are provided.

Embodiments of the present invention will be described below with reference to the drawings.
Note that the drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the ratio coefficient of the size between the parts, and the like are not necessarily the same as actual ones. Further, even when the same part is represented, the dimensions and ratio coefficient may be represented differently depending on the drawing.
Further, in the present specification and each drawing, the same reference numerals are given to the same elements as those described above with reference to the previous drawings, and detailed description thereof will be omitted as appropriate.

(First embodiment)
FIG. 1 is a schematic view illustrating the configuration of a superconducting wire according to the first embodiment of the invention. FIG. 2 is a schematic cross-sectional view illustrating the configuration of the superconducting wire according to the first embodiment of the invention.
1A is a schematic perspective view, FIG. 1B is a plan view when viewed from the V direction of FIG. 1A, and FIG. It is AA 'line sectional drawing of.
FIG. 2 is a cross-sectional view corresponding to the cross-sectional view illustrated in FIG. 1C and illustrates one specific example of the structure of the superconducting wire in more detail.

  As shown in FIG. 1, the superconducting wire according to the first embodiment of the present invention includes a first superconducting wire 100, a second superconducting wire 200, and a c-axis surface 111 that is a main surface of the first superconducting wire 100. And a c-axis surface 211 that is the main surface of the second superconducting wire 200, and a superconducting connector 300 that electrically connects the first superconducting wire 100 and the second superconducting wire 200. .

  The first superconducting wire 100 has a first superconducting layer 140 provided on the first base 120, for example. On the other hand, the second superconducting wire 200 has a second superconducting layer 240 provided on the second base material 220, for example.

  For the first base material 120 and the second base material 220, for example, a metal tape can be used, and as the material, for example, Ni-W can be used.

For the first superconducting layer 140 and the second superconducting layer 240, for example, YBa ₂ Cu ₃ O _7-x (hereinafter referred to as YBCO) which is an yttrium-based superconducting material can be used. YBCO is a superconductor having a perovskite structure. Further, for the first superconducting layer 140 and the second superconducting layer 240, a material obtained by replacing a lanthanoid rare earth element with yttrium or a mixture thereof can be used.

In addition, as illustrated in FIG. 2, for example, non-oriented Hastelloy-C layers 130 and 230 can be provided on the first substrate 120 and the second substrate 220. Further, Y-stabilized ZrO ₂ layers (hereinafter referred to as YSZ layers) are provided thereon as the orientation layers 131 and 231 having orientation, for example, by Ion-beam-assisted deposition (IBAD). Further thereon, CeO ₂ layers are provided as the intermediate layers 132 and 232 having orientation by, for example, a pulse laser deposition (PLD) method. Furthermore, a YBCO layer is provided thereon as the first superconducting layer 140 and the second superconducting layer 240.

  As described above, the first base material 120 and the second base material 220 do not have an alignment layer, and layers having orientation properties such as the alignment layers 131 and 231 and the intermediate layers 132 and 232 are provided thereon. The first superconducting layer 140 and the second superconducting layer 240 may be provided thereon. Moreover, the surface of the 1st base material 120 and the 2nd base material 220 has orientation, provides the intermediate | middle layers 132 and 232 on it, and provides the 1st superconducting layer 140 and the 2nd superconducting layer 240 on it, respectively. It can be configured.

  The first superconducting layer 140 and the second superconducting layer 240 have c-axis orientation. That is, it is a layer having biaxial orientation, the a-axis and b-axis are substantially parallel to the layer surfaces of the first superconducting layer 140 and the second superconducting layer 240, and the c-axis is substantially to the layer surface. Vertically oriented.

  Thereby, the 1st superconducting wire 100 (namely, 1st superconducting layer 140) and the 2nd superconducting wire 200 (namely, 2nd superconducting layer 240) have biaxial orientation. As shown in FIG. 1, the c-axis 110 of the first superconducting wire 100 and the c-axis 210 of the second superconducting wire 200 are respectively the main surface of the first superconducting wire 100 and the second superconducting wire. Each is substantially perpendicular to the main surface of the line 200. That is, the c-axis surface 111 of the first superconducting wire 100 and the c-axis surface 211 of the second superconducting wire 200 are respectively on the main surface of the first superconducting wire 100 and the main surface of the second superconducting wire 200. On the other hand, they are substantially parallel to each other.

  Note that the a-axis and b-axis of the first superconducting wire 100 are in a plane substantially parallel to the main surface of the first superconducting wire 100. Here, the a-axis and the b-axis of the first superconducting wire 100 can be set at an arbitrary angle with respect to the extending direction of the first superconducting wire 100. In many cases, it is 45 degrees or 0 degrees in the manufacturing method of the alignment substrate and the intermediate layer. Similarly, the a-axis and b-axis of the second superconducting wire 200 are in a plane substantially parallel to the main surface of the second superconducting wire 200. Here, the a-axis and the b-axis of the second superconducting wire 200 can be at an arbitrary angle with respect to the extending direction of the second superconducting wire 200. In many cases, it is 45 degrees or 0 degrees in the manufacturing method of the alignment substrate and the intermediate layer.

  The superconducting connector 300 is opposed to the c-axis surface 111 of the first superconducting wire 100 (ie, the first superconducting layer 140) and the c-axis surface 211 of the second superconducting wire 200 (ie, the second superconducting layer 240). Is provided. As a result, the superconducting connector 300 superconductingly connects the first superconducting wire 100 and the second superconducting wire 200. At this time, the c-axis 310 of the superconducting connector 300 is substantially perpendicular to the c-axis surface 111 of the first superconducting wire 100 and the c-axis surface 211 of the second superconducting wire 200. That is, the c-axis 310 of the superconducting connector 300 is substantially parallel to the c-axis 110 of the first superconducting wire 100 and the c-axis 210 of the second superconducting wire 200.

  As shown in FIG. 1C, for example, when a current flows from the first superconducting wire 100 toward the second superconducting wire 200, the first superconducting wire 100 has a portion of the first superconducting wire 100. A current flows in a direction parallel to the main surface (in the direction of arrow a1). That is, current flows in a direction perpendicular to the c-axis 110 of the first superconducting wire 100.

  In the connection region where the first superconducting wire 100 and the superconducting connector 300 overlap, the current flows in the direction perpendicular to the main surface of the first superconducting wire 100 (the direction of the arrow a2). That is, it flows in a direction parallel to the c-axis 110 of the first superconducting wire 100.

  In superconducting connector 300, a current flows in a direction parallel to the main surface of superconducting connector 300 (in the direction of arrow a3). That is, it flows in a direction perpendicular to the c-axis 310 of the superconducting connection body 300.

  In the connection region where superconducting connector 300 and second superconducting wire 200 overlap, current flows in a direction perpendicular to the main surface of second superconducting wire 200 (in the direction of arrow a4). That is, it flows in a direction parallel to the c-axis 210 of the second superconducting wire 200.

  In the portion of the second superconducting wire 200, a current flows in a direction parallel to the main surface of the second superconducting wire 200 (the direction of the arrow a5). That is, a current flows in a direction perpendicular to the c-axis 210 of the second superconducting wire 200.

  On the contrary, the case where a current is passed from the first superconducting wire 100 to the second superconducting wire 200 is the same as the above except that the direction of the current is different.

Thus, current flows in the directions of arrows a1 to a5. At this time, when the direction of current flows in a direction perpendicular to the c-axis of the superconducting material, that is, in the direction of arrows a1, a3, and a5, the critical current density (Jc) is large and 3 MA / cm ^2. A superconducting current flows with a Jc value of about.

  On the other hand, when the direction of current flows in a direction parallel to the c-axis of the superconducting material, that is, when flowing in the directions of arrows a2 and a4, the resistance value rises more than when flowing in the vertical direction. For example, the Jc value when the current direction is parallel to the c-axis is reduced to about 1/100 to 1/1000 compared to when the current direction is perpendicular. At this time, by sufficiently increasing the area of the connection region where the superconducting connection body 300 and the first and second superconducting wires 100 and 200 overlap, a connection portion having a low Jc value is not substantially a problem.

For example, the layer thicknesses of the first superconducting layer 140 of the first superconducting wire 100 and the second superconducting layer 240 of the second superconducting wire 200 can be set to about 1 μm, for example. On the other hand, the length in the extending direction of the connection region where the superconducting connector 300 and the first and second superconducting wires 100 and 200 overlap is, for example, 0.1 mm to 1 mm (that is, 100 to 1000 times the layer thickness of 1 μm). ), The superconducting current flowing through the superconducting wires 100 and 200 is sufficiently eliminated by sufficiently eliminating the connection portion at a low Jc value in the connecting region where the superconducting connector 300 and the first and second superconducting wires 100 and 200 overlap. Will flow without being disturbed. The resistance value at this time is 1.0 × 10 ⁻¹² Ω because resistance is generated mainly by the connecting portion.

As described above, the area where the first superconducting wire 100 and the superconducting connector 300 are opposed to each other is the breakage of the first superconducting layer 140 of the first superconducting wire 100 in a plane orthogonal to the extending direction of the first superconducting wire 100. It can be 100 times or more of the area.
The area where the second superconducting wire 200 and the superconducting connector 300 face each other is the cross-sectional area of the second superconducting layer 240 of the first superconducting wire 200 in a plane orthogonal to the extending direction of the second superconducting wire 200. It can be 100 times or more.

  As described above, according to the superconducting wire 10 according to the present embodiment, a superconducting wire in which the superconducting current is not inhibited even at the joint portion can be obtained by connecting the superconducting wire with a superconducting wire having the same critical current (Ic).

  In the above specific example, the c-axis of the superconducting connector 300 is parallel to the c-axis of the first and second superconducting layers 140 and 240 of the first and second superconducting wires 100 and 200. As described above, the direction of the c-axis of the superconducting connector 300 is arbitrary. However, when the c-axis of the superconducting connector 300 is parallel to the c-axis of the first and second superconducting layers 140 and 240, the superconducting connector 300 and the first and second superconducting layers 140, Since the continuity of the structure is maintained at the interface with 240, it is desirable because stable superconducting connection can be easily obtained.

(Comparative example)
FIG. 3 is a schematic cross-sectional view illustrating the configuration of a superconducting wire of a comparative example.
That is, FIGS. 9A to 9C illustrate the configuration of the superconducting wires of the first to third comparative examples.
As shown in FIG. 3A, in the superconducting material 91 of the first comparative example, the first and second superconducting layers 140 and 240 of the first and second superconducting wires 100 and 200 are on the same side. The first and second superconducting wires 100 and 200 are arranged, and a connecting material 510 made of, for example, normal conducting solder is provided thereon. Thereby, the first superconducting wire 100 and the second superconducting wire 200 are connected. In this case, the connecting material 510 is a normal conductor, and has a resistance value that is not comparable to a superconductor having a resistance value of zero. Therefore, even if the area of the connection region between the first and second superconducting wires 100 and 200 and the connecting material 510 is increased as much as practically possible, the connection can maintain the Jc value of the superconducting wire 91. I can't. At this time, when the resistance value of the connection portion is measured, the value is 1.0 × 10 ⁻⁶ Ω or more.

As shown in FIG. 3B, in the superconducting material 92 of the second comparative example, the first and second superconducting layers of the first and second superconducting wires 100 and 200 face each other. Two superconducting wires 100 and 200 are arranged and connected by a connecting material 520 made of, for example, silver. That is, the first and second superconducting wires 100 and 200 which are biaxially oriented superconductors are joined via the silver thin film. Also in this case, the connecting material 520 is a normal conductor and has a very large resistance value as compared with the superconductor. The connection resistance at this time is 1.0 × 10 ⁻⁹ Ω when the length of the connecting material 520 is 10 cm. This structure is a structure disclosed in Patent Document 1, for example, and has a large resistance value, for example, about 1.0 × 10 ⁻⁹ Ω. If an attempt is made to realize at this structure 1.0 × ^{10- 12} Ω, the length of the connecting member 520 is required 1000 times 100m above 10 cm, practically become unrealistic long joint End up.

  Further, as shown in FIG. 3C, in the superconducting material 93 of the third comparative example, the surfaces of the superconducting layers of the first and second superconducting wires 100 and 200 are juxtaposed, and between the respective end portions, That is, a connecting material 530 made of a superconducting material is provided between the first superconducting layer 140 and the second superconducting layer 240 in the gap between the first and second superconducting wires 100 and 200. In the gap between the first and second superconducting wires 100 and 200, a portion other than between the first superconducting layer 140 and the second superconducting layer 240 is filled with a filler 531 and the first and second superconducting wires 100 and 200 are filled. Superconducting wires 100 and 200 and connecting material 530 are supported.

In the case of this structure, the connecting member 530 is in a direction perpendicular to the c-axis showing low resistance in the first and second superconducting wires 100 and 200 (that is, a direction parallel to a plane including the a-axis and the b-axis). The first superconducting wire 100 and the second superconducting wire 100 are connected. Therefore, the direction of current flow in this case is a direction perpendicular to the c-axis, and a superconducting current having zero resistance can be expected. However, a biaxially oriented superconductor characterized by atomic level orientation has a structure in which gaps are formed at most of the ends at the end. For this reason, a superconducting current cannot be obtained at the interface between the first and second superconducting wires 100 and 200 and the connecting member 530. That is, even if the end surfaces of the first and second superconducting wires 100 and 200 are processed and a superconducting layer is formed on the end surfaces again, the superconducting current is interrupted due to damage to the portion, and the superconducting level is low. Connection with resistors cannot be realized.
As described above, in the superconducting wires 91 to 93 of the comparative example, it is not possible to realize a connection that allows a superconducting current to flow with a sufficiently low resistance value.

  On the other hand, in the superconducting wire 10 according to the present embodiment, the superconducting connection body 300 provided to face the c-axis surface 111 of the first superconducting wire 100 and the c-axis surface 211 of the second superconducting wire 200 is used. . Thereby, the orientation at the atomic level can be maintained at the interface between the first superconducting wire 100 and the second superconducting wire 200 and the superconducting connector 300, and the superconductivity is not lost.

  At this time, in the region where the first superconducting wire 100 and the second superconducting wire 200 overlap with the superconducting connector 300, current flows in a direction parallel to the c-axis. 2 When the current flows through the superconducting wires 100 and 200, the Jc value may be 1/100 to 1/1000. For this, the first superconducting wire 100 and the second superconducting wire 200 and the superconducting connector 300 are easily eliminated by enlarging the area of the overlapping region, and the low Jc value of the current path passing through the connecting portion is not a problem.

  Thus, according to the superconducting wire 10 according to the present embodiment, a superconducting wire in which the superconducting wires are connected at a high critical current density can be obtained.

FIG. 4 is a schematic plan view illustrating the configuration of a modification of the superconducting wire according to the first embodiment of the invention.
As shown in FIG. 4A, in the superconducting wire 10a according to this embodiment, the widths of the first superconducting wire 100, the second superconducting wire 200, and the superconducting connector 300 connecting them are substantially the same. is there. These side surfaces (surfaces parallel to the extending direction and perpendicular to the main surface) are substantially coincident. By doing so, the first superconducting wire 100 and the second superconducting wire 200 can flow a current over the entire length in the width direction, so that the efficiency is high.

Furthermore, as shown in FIG. 4B, in the superconducting wire 10b of the modified example according to the present embodiment, the widths of the first superconducting wire 100 and the second superconducting wire 200 are substantially the same. The width of the superconducting connection body 300 is longer than the widths of the first superconducting wire 100 and the second superconducting wire 200. Also in this case, the first superconducting wire 100 and the second superconducting wire 200 can pass a current over the entire length in the width direction, and further, near the side surfaces of the first superconducting wire 100 and the second superconducting wire 200. It is possible to prevent a decrease in current capacity.
Then, when providing the superconducting connector 300 on the first superconducting wire 100 and the second superconducting wire 200, a support material (not shown) for fixing and supporting the first superconducting wire 100 and the second superconducting wire 200 is provided. Sometimes. At this time, the support material can be made wider than the widths of the first and second superconducting wires 100 and 200 and can be stably supported. At this time, the superconducting connector 300 can be provided in accordance with the shape of the support material. At this time, the width of the superconducting connector 300 is wider than the width of the first and second superconducting wires 100 and 200. Thereby, the mechanical strength of a connection part can be raised more.

In addition, as shown in FIG. 4C, in the superconducting wire 10c of the modified example according to the present embodiment, the widths of the first superconducting wire 100 and the second superconducting wire 200 are substantially the same. The width of the superconducting connection body 300 is smaller than the width of the first superconducting wire 100 and the second superconducting wire 200. When the first superconducting wire 100 and the second superconducting wire 200 are juxtaposed and connected by the superconducting connector 300, the widths of the first superconducting wire 100, the second superconducting wire 200, and the superconducting connector 300 are the same. When these positions are shifted, irregularities along the extending direction of the superconducting wire are generated. On the other hand, the first superconducting wire 100 and the second superconducting wire are formed by making the width of the superconducting connector 300 narrower than the widths of the first and second superconducting wires 100 and 200 as in this modification. If the positions of the superconducting connector 300 are slightly deviated from each other, the unevenness does not occur. As described above, by allowing the width of the superconducting connection body 300 to be narrower than the widths of the first and second superconducting wires 100 and 200, the tolerance of the alignment accuracy of the superconducting connection body 300 is widened. Thereby, a manufacturing margin is widened and a superconducting wire that is easy to make can be provided.
In addition, for example, the design of the jig used when forming the superconducting connector 300 on the first and second superconducting wires 100, 200, the width of the superconducting connector 300 is the first, second superconducting wire 100, It can be designed to be thinner than 200 widths. As a result, the tolerance of positional accuracy when the first and second superconducting wires 100 and 200 are installed on the jig is expanded. This also widens the manufacturing margin and provides a superconducting wire that is easy to make.
In addition, when there is a concern that the Jc value decreases when the width of the superconducting connector 300 is narrowed, the connection length between the first and second superconducting wires 100 and 200 and the superconducting connector 300 is concerned. This can be dealt with by increasing the contact area and widening the contact area, and this is not a problem in practice.

  Further, as shown in FIG. 4D, in the superconducting wire 10d of the modification according to the present embodiment, the widths of the first and second superconducting wires 100 and 200 are substantially the same. The end faces of the two superconducting wires 100 and 200 are joined so as not to coincide with each other. Thus, even if the end surfaces of the first and second superconducting wires 100 and 200 are shifted, a low-resistance connection can be obtained.

  Further, as shown in FIG. 4E, in the superconducting wire 10e of the modified example according to the present embodiment, the widths of the first and second superconducting wires 100 and 200 are substantially the same. The side surfaces of the two superconducting wires 100 and 200 are joined so as not to coincide with each other. The superconducting connection body 300 is provided with a width wider than the width of the first and second superconducting wires 100 and 200. Also in this case, a low resistance connection can be realized. Further, the mechanical strength of the connection between the first and second superconducting wires 100 and 200 can be reinforced at the portion where the end surface of the superconducting connector 300 protrudes from the side surfaces of the first and second superconducting wires 100 and 200. And a higher strength superconducting wire can be obtained.

  Further, as shown in FIG. 4F, in the superconducting wire 10f of the modification according to the present embodiment, the width of the first superconducting wire 100 and the width of the second superconducting wire 200 are different from each other. . Thus, even when the width of the first superconducting wire 100 and the width of the second superconducting wire 200 are different from each other, a low resistance connection is possible.

  As described above, the connection technique according to this embodiment can be applied not only to connection of superconducting wires having the same line width, but also to connection of superconducting wires having different line widths, for example. Furthermore, for example, the present invention can be applied to connection of superconducting wires having different thicknesses, and can also be applied to connection of superconducting wires using different materials, as will be described in Examples described later.

FIG. 5 is a schematic plan view illustrating the configuration of a modified example of the superconducting wire according to the first embodiment of the invention.
As shown in FIG. 5A, in the superconducting wire 10g of the modification according to this embodiment, the first superconducting wire 100 and the second superconducting wire 200 are adjacent to each other in the direction orthogonal to the extending direction. The superconducting connection body 300 is provided on them. That is, the first and second superconducting wires 100 are arranged such that the side surface parallel to the extending direction of the first superconducting wire 100 and the side surface parallel to the extending direction of the second superconducting wire 200 face each other. , 200 are juxtaposed. Thus, by arranging the first superconducting wire 100 and the second superconducting wire 200 in a direction orthogonal to the extending direction, the first superconducting wire 100 and the second superconducting wire 200 are adjacent to each other. Can be expanded.

That is, for example, in the case of the superconducting wires 10a to 10f illustrated in FIGS. 4A to 4F, the length of the first superconducting wire 100 and the second superconducting wire 200 adjacent to each other is the first superconducting wire 100. In the superconducting wire 10g illustrated in FIG. 5 (a), the first superconducting wire 100 and the second superconducting wire 200 are arranged in the extending direction. By arranging them in a direction perpendicular to each other, the length of the first superconducting wire 100 and the second superconducting wire 200 adjacent to each other can be arbitrarily increased. This makes it easier to compensate for the decrease in Jc value.
For example, the length of the first superconducting wire 100 and the second superconducting wire 200 adjacent to each other can be 10 times or more the line width of the first superconducting wire 100 and the second superconducting wire 200.

  Further, as shown in FIG. 5B, in the superconducting wire 10h of the modification according to this embodiment, the first superconducting wire 100 and the second superconducting wire 200 are orthogonal to the extending direction. Two superconducting connectors 300 are provided adjacent to each other. This allows a larger current to flow. Thus, a plurality of superconducting connectors 300 can be provided.

  When a plurality of superconducting connectors 300 are provided, the first superconducting wire 100 and the second superconducting wire 200 are connected in series in the extending direction as in the superconducting wires 10a to 10f illustrated in FIGS. If the first and second superconducting wires 100 and 200 are adjacent to each other, the length of the adjacent first and second superconducting wires 100 and 200 is substantially the same as the width thereof, so that the width is reduced and a plurality of superconducting connectors 300 are provided. It is likely to be difficult. On the other hand, like the superconducting wire 10h illustrated in FIG. 5B, the first and second superconducting wires are arranged in the direction orthogonal to the extending direction by arranging the first and second superconducting wires 100 and 200. The length in which the wires 100 and 200 are adjacent to each other can be increased, and a plurality of superconducting connectors 300 can be easily provided. This prevents a decrease in the current value at the connecting portion and realizes a stable superconducting connection.

  As shown in FIG. 5C, in the superconducting wire 10i of the modification according to the present embodiment, the line width of the first superconducting wire 100 and the line width of the second superconducting wire 200 are different from each other. . That is, in the example of FIG. 5C, the line width of the second superconducting wire 200 is narrower than that of the first superconducting wire 100. And the 1st superconducting wire 100 and the 2nd superconducting wire 200 are arrange | positioned adjacent to the direction orthogonal to the extending direction, and the superconducting connection body 300 is provided on them.

  At this time, for example, when the first and second superconducting wires 100 and 200 are arranged in series along the extending direction as in the superconducting wire 10f illustrated in FIG. 4F, the first superconducting wire 100 and The length of the second superconducting wire adjacent to each other is determined by the line width of the narrower one (in this case, the second superconducting wire 200), and it may be difficult to increase the current value that the wire can accept. At this time, like the superconducting wire 10i illustrated in FIG. 5C, the first and second superconducting wires 100 and 200 are juxtaposed in the direction orthogonal to the extending direction, so that the first superconducting wire 100 and the first superconducting wire 100 The length of the two superconducting wires 200 adjacent to each other can be increased, and the current capacity can be easily increased.

  Also in the superconducting wires 10a to 10i of the various modifications described above, a superconducting wire obtained by superconducting connection of superconducting wires that can obtain a sufficient superconducting current can be obtained.

In the superconducting wires 10, 10a to 10i according to the present embodiment, the width of the first superconducting wire 100 and the width of the second superconducting wire 100 can be 5 A or more. That is, the current flowing through the first superconducting wire 100, the superconducting connector 300, and the second superconducting wire 200 can be 5 A or more per 1 cm of the width of the first superconducting wire 100 and the width of the second superconducting wire 100.
Furthermore, the width of the first superconducting wire 100 and the width of the second superconducting wire 100 can be 30 A or more per 1 cm. That is, the current flowing through the first superconducting wire 100, the superconducting connector 300, and the second superconducting wire 200 can be 30 A or more per 1 cm of the width of the first superconducting wire 100 and the width of the second superconducting wire 100.

  In the superconducting wire rods 10, 10 a to 10 i according to the present embodiment, this can be realized by connecting the first and second superconducting wires 100, 200 in a superconducting state by the superconducting connection body 300.

  Thus, for example, in the joining of the ends of superconducting wires having a biaxially oriented structure on the intermediate layer of two different wires, the conventional technology deteriorates and the allowable amount of superconducting current is reduced in the prior art. However, according to the superconducting wire according to the present embodiment, the superconducting junction is realized by performing connection in the c-axis direction in a state where the growth directions of the biaxially oriented structures are roughly matched. At this time, since the superconducting current obtained in the c-axis direction is said to be about 1/100 of the a-axis direction, for example, the area of the connection surface is 100 times the thickness of the superconducting layer of the superconducting wire. By setting it as the above, the superconducting connection by the low resistance biaxial orientation structure | tissue connected by the superconductivity can be implement | achieved practically solving the allowable amount fall of a superconducting current.

At this time, the same material as the superconducting layers 140 and 240 of the first and second superconducting wires 100 and 200 can be used for the superconducting layer to be the superconducting connector 300.
However, it is desirable to use a material of a different type from the superconducting layers 140 and 240 of the first and second superconducting wires 100 and 200 for the superconducting layer that becomes the superconducting connector 300. For example, SmBa ₂ CuO _7-x can be used as the material of the superconducting layer to be the superconducting connection body 300.

  That is, as a superconducting layer to be the superconducting connection body 300, by using a different kind of material from the first and second superconducting layers 140 and 240 of the first and second superconducting wires 100 and 200, the lattice constant is different. Since pinning centers can easily enter and self-orientation can be expected, continuity with the surfaces of the first and second superconducting layers 140 and 240 can be easily maintained, and stable superconducting connection can be easily obtained.

  Therefore, it is desirable to use a material different from the material contained in the first and second superconducting wires 100 and 200 to be connected as the material used for the superconducting connector 300. That is, it is desirable that superconducting connector 300 includes an element different from the element included in first superconducting layer 140 of first superconducting wire 100. In addition, it is desirable that superconducting connector 300 includes an element different from the element included in second superconducting layer 240 of second superconducting wire 200.

  For example, lanthanoids that express superconductivity include La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. In addition, as a material that develops superconductivity, a material containing yttrium (Y) can be given. Therefore, the superconducting connector 300 is different from the elements contained in the first and second superconducting layers 140 and 240, La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y. At least one selected from the group consisting of:

(First embodiment)
Hereinafter, a first example according to this embodiment will be described.
FIG. 6 is a schematic view illustrating the configuration of the superconducting wire according to the first embodiment of the invention.
1A is a schematic perspective view, FIG. 1B is a plan view when viewed from the V direction of FIG. 1A, and FIG. It is AA 'line sectional drawing of.

As shown in FIG. 6, the superconducting wire 11 according to the first embodiment includes a first superconducting wire 100 and a second superconducting wire 200.
The lengths of the first superconducting wire 100 and the first superconducting wire 200 are about 50 cm, respectively. One end of the first superconducting wire 100 is 1A, and one end of the second superconducting wire 200 is 1B.

  A guide C and a guide D are attached to one end 1A and 1B of the first and second superconducting wires 100 and 200, respectively. For these guides 1C and 1D, Hastelloy-C can be used.

In the first and second superconducting wires 100 and 200, the Hastelloy-C layer 130 having no orientation was provided on the base material 120 or 220 such as a metal tape, and the film was formed thereon by the IBAD method. Alignment layers 131 and 231 composed of ZrO ₂ layers (hereinafter referred to as YSZ layers) in which Y ₂ O ₃ is blended at 8 mol% are provided, and further an intermediate layer 132 composed of CeO ₂ formed by the PLD method. 232 is provided. On top of this, first superconducting layers 140 and 240 made of a YBCO layer are provided.

  The total thickness of the first superconducting wire 100 and the second superconducting wire 200 is about 0.1 mm. The thicknesses of the alignment layers 131 and 231, the intermediate layers 132 and 232, and the first and second superconducting layers 140 and 240 are, for example, about 1 μm, about 0.2 μm, and about 1 μm, respectively.

One ends 1A and 1B of the first and second superconducting wires 100 and 200 are respectively attached to guides 1C and 1D to be fixed, and the one ends 1A and 1B are fixed so as not to move.
Hereinafter, the connection portion with the first and second superconducting wires 100 and 200 will be referred to as a processed portion 1X.

The workpiece 1X is placed in a PLD method chamber, and a YBCO film is formed using a Kr-F laser. The temperature of the part 1X to be processed is, for example, 775 ° C., and the oxygen partial pressure can be 300 mTorr. Then, using a YBa ₂ Cu ₃ O ₆ target, film formation is performed at an energy density of 1.8 J / cm ² . The film thickness of the YBa ₂ Cu ₃ O ₆ film is about 1 μm, and the film can be formed while monitoring with a detector in the chamber.

  Furthermore, the workpiece 1X is subjected to oxygen annealing in a separate electric furnace in 100% oxygen gas at 450 ° C. for 1 hour to obtain a superconducting film made of a YBCO film.

  After cooling the electric furnace, the workpiece 1X is taken out from the electric furnace, and the superconducting wire 11 of this embodiment is obtained.

The superconducting wire 11 is cooled in liquid nitrogen inside the magnetic shield, a magnetic field is applied, the current is maintained in the permanent current mode, and the magnetic flux of the superconducting wire connected by the Hall element is measured after a certain time. As a result, the initial current value is 6 A, and the resistance of the superconducting connection part (processed part 1X) at this time is 3.2 × 10 ⁻¹³ Ω.

  In addition, since the width | variety of the 1st, 2nd superconducting wire 100,200 is 4 mm width, in the superconducting wire 1 of a present Example, it is equivalent to having obtained the critical current value of 15 A per 1 cm width.

  Thus, the superconducting wire 11 which connected the superconducting wire with the superconductor can be provided by the superconducting wire 11 which concerns on a 1st Example.

(Second Embodiment)
In the superconducting wire according to the second embodiment of the present invention, in the first embodiment, an embedding material is provided in the gap between the first and second superconducting wires. The rest is the same as the first embodiment. Therefore, this embedding material will be described.

FIG. 7 is a schematic cross-sectional view illustrating the configuration of a superconducting wire according to the second embodiment of the invention.
That is, this figure is a schematic cross-sectional view corresponding to the cross section along line AA ′ of FIG.
As shown in FIG. 7, in the superconducting wire 20 according to the second embodiment of the present invention, the embedding material 410 is provided in the gap between the first superconducting wire 100 and the second superconducting wire 200.
For the filling material 410, for example, various metals can be used.

  As described above, by filling the gap between the first and second superconducting wires 100 and 200 with the filling material 410, the mechanical strength of the gap portion between the first and second superconducting wires 100 and 200 is improved.

  As described above, the superconducting wire 20 according to the second embodiment can provide a superconducting wire having a high mechanical strength at the connection portion while connecting the superconducting wire with a high critical current density.

  In the above description, the first and second superconducting wires 100 and 200 are arranged in series along the extending direction as illustrated in FIGS. 4 and 5, for example. Alternatively, the first and second superconducting wires 100 and 200 may be arranged in a direction orthogonal to the extending direction. In these arrangements, a filling material can be provided in the gap between the first and second superconducting wires 100 and 200.

(Third embodiment)
In the superconducting wire according to the third embodiment of the present invention, a step adjusting material used when the thicknesses of the first and second superconducting wires are different is further provided. Other than this, it can be the same as the first and second embodiments. Below, in the superconducting wire 20 which concerns on 2nd Embodiment, it demonstrates as a case where a level | step difference adjustment material is further provided.

FIG. 8 is a schematic cross-sectional view illustrating the configuration of a superconducting wire according to the third embodiment of the invention.
That is, this figure is a schematic cross-sectional view corresponding to the cross section along line AA ′ of FIG.
As shown in FIG. 8, in the superconducting wire 30 according to the third embodiment of the present invention, at least one of the first superconducting wire 100 and the second superconducting wire 200 is opposite to the surface facing the superconducting connector 300. The step adjusting member 420 is further provided for adjusting the step of the surface of the first superconducting wire 100 and the second superconducting wire 200.
That is, the level difference adjusting material 420 reduces the level difference between the surfaces of the first superconducting wire 100 and the second superconducting wire 200 facing the superconducting connector 300.

  That is, for example, as described in the first embodiment, the one ends 1A and 1B of the first and second superconducting wires 100 and 200 are attached to the fixing guides 1C and 1D (Hastellloy-C layer), respectively. Fix 1A and 1B so that they do not move.

  The surfaces of the first and second superconducting wires 100 and 200 on the first and second superconducting layers 140 and 240 side (superconducting connection) in a state where the ends 1A and 1B are fixed to the fixing guides 1C and 1D, respectively. The surface of the first and second superconducting wires 100 and 200 on the first and second superconducting layers 140 and 240 side is reduced based on the measurement result. A step adjusting member 420 having a large step can be arranged on the guide 1C and guide 1D side. Thereby, the level | step difference of the surface by the side of the 1st, 2nd superconducting layer 140,240 of the 1st, 2nd superconducting wire 100,200 can be made uniform. For example, the step on the superconducting layer side of the first and second superconducting wires 100 and 200 can be set to 0.05 μm or less.

  Thereby, disorder of the orientation in the superconducting connector 300 caused by the step between the first and second superconducting wires 100 and 200 can be suppressed, and the superconducting connector 300 having a good orientation can be obtained.

  As described above, the superconducting wire 30 according to the third embodiment improves the orientation of the superconducting connection body and connects the superconducting wire with a superconductor having a large allowable current, thereby connecting the superconducting wire with a sufficiently low resistance. Can be provided.

  If the difference in thickness between the first and second superconducting wires 100 and 200 is known, the above step measurement is not necessary. If the thicknesses of the first and second superconducting wires 100 and 200 are substantially the same, the step adjusting member 420 can be omitted.

(Fourth embodiment)
FIG. 9 is a schematic view illustrating the configuration of a superconducting wire according to the fourth embodiment of the invention. 1A is a schematic perspective view, FIG. 1B is a plan view when viewed from the V direction of FIG. 1A, and FIG. It is AA 'line sectional drawing of.
As shown in FIG. 9, the superconducting wire 40 according to the fourth embodiment of the present invention includes a first superconducting wire 100, a second superconducting wire 200, a c-axis surface 111 of the first superconducting wire 100, And a superconducting connector 300 that is provided opposite to the c-axis surface 211 of the two superconducting wires 200 and electrically connects the first superconducting wire 100 and the two superconducting wires 200.

  The first superconducting wire 100 has a first superconducting layer 140 provided on the superconducting connector 300 side of the first superconducting wire 100, and the second superconducting wire 200 is the superconducting connector 300 of the second superconducting wire 200. The second superconducting layer 240 is provided on the side.

  The first superconducting layer 140 and the second superconducting layer 240 are set back from the surface where the first superconducting wire 100 and the second superconducting wire 200 face each other. That is, the first superconducting layer 140 and the second superconducting layer 240 are set back from the one end 1A of the first superconducting wire 100 and the one end 1B of the second superconducting wire 200, respectively.

  The recessed part of the first superconducting layer 140 and the recessed part of the second superconducting layer 240 can be formed by etching, for example.

An alignment layer (connection alignment layer 435) is formed on the first superconducting wire 100 where the first superconducting layer 140 has receded and on the second superconducting wire 200 where the second superconducting layer 240 has receded. Provided. Then, the superconducting connection body 300 is provided on the connection orientation layer 435.
That is, the superconducting wire 40 is provided between the first superconducting wire 100 where the first superconducting layer 140 has receded and the second superconducting wire 200 where the second superconducting layer 240 has receded, and the superconducting connector 300. The connection orientation layer 435 is further provided.

The connection alignment layer 435 may include a connection portion alignment layer 431 and a connection portion intermediate layer 432 provided thereon. For example, as the connection portion alignment layer 431, for example, a Y-stabilized ZrO ₂ layer formed by the IBAD method can be used. Then, as the connecting portion intermediate layer 432, it can be used CeO ₂ layer formed by, for example, a PLD method.

  Then, on the connection orientation layer 435 (the connection part orientation layer 431 and the connection part intermediate layer 432), for example, a YBCO layer that becomes the superconducting connection body 300 is formed.

That is, in the first to third embodiments, the superconducting connector 300 is provided on the first and second superconducting layers 140 and 240 of the first and second superconducting wires 100 and 200. In some cases, the disorder of orientation occurs at the interface between 300 and the first and second superconducting layers 140 and 240, making it difficult to obtain a superconducting connection. At this time, like the superconducting wire 40 according to the present embodiment, the first and second superconducting layers 140 and 240 are partially removed from the connection portion, and a new alignment layer (connection alignment layer 435) is provided at that portion. Thus, the orientation of the superconducting connector 300 can be improved, a good superconducting connection can be realized, and a large current can flow.
As described above, according to the superconducting wire 40 according to the present embodiment, the orientation of the superconducting connection body is further improved, and the superconducting wire is connected with the superconducting wire with a superconductor having a large current allowance. The superconducting wire made can be provided.

  In this case as well, the filling material 410 can be provided in the gap between the first superconducting wire 100 and the second superconducting wire 200.

  That is, in the superconducting wire 40 according to the present embodiment, the portion where the underlying biaxially oriented structure is interrupted in the superconducting connection is connected with higher quality. That is, a new alignment layer (connection alignment layer 435) is provided to allow a state where a gap is slightly opened between the superconducting wires.

FIG. 10 is a schematic cross-sectional view in order of the processes, illustrating a method for manufacturing a superconducting wire according to the fourth embodiment of the invention.
As shown in FIG. 10, the end portions of the first and second superconducting wires 100 and 200 are shaped by, for example, laser cutting so that the gap between the first and second superconducting wires 100 and 200 to be connected is minimized. Align.

  First and second superconducting wires 100 and 200 are attached to guides 1C and 1D, respectively. Then, the heights of the surfaces of the first and second superconducting layers 140 and 240 of the first and second superconducting wires 100 and 200 are measured, and a step adjusting material 420 provided with a step corresponding thereto is attached.

  Then, as illustrated in FIG. 10B, the gap between the first and second superconducting wires 100 and 200 is filled with the filling material 410.

Then, as shown in FIG. 10C, a mask 450 such as a slit is provided to expose the connecting portions of the first and second superconducting wires 100 and 200 and cover other portions, and etching is performed. Machined to a certain depth by milling or milling. The depth of cutting may be any position as long as it is sufficient to form the alignment layer later.
For example, two superconducting wires in which the gap is filled are etched in the depth direction by, for example, about 1 μm by, for example, ion milling. By this etching, for example, the intermediate layers 132 and 232 (CeO ₂ layer) and the alignment layers 131 and 2331 (IBAD layer) which are the base layers from the first and second superconducting layers 140 and 240 (YBCO layer) are formed. Exposed. Note that the depth of etching may be increased to expose, for example, the Hastelloy-C layers 130 and 230 and the Ni—W layer serving as the first base materials 120 and 220 under the etching.
Since such a surface is a layer damaged in the orientation, even if YBCO film formation is performed thereon, it may be difficult to exhibit superconducting characteristics. For this reason, a connection orientation layer 435 is provided in the shaved portion as described below.

That is, as shown in FIG. 10D, a connection portion alignment layer 431 made of, for example, Gd ₂ Zr ₂ O ₇ is formed on the exposed portion exposed by cutting, for example, by the IBAD method. The IBAD method is a method for obtaining an alignment layer even on a non-oriented surface. Further, a connection intermediate layer 432 such as a CeO ₂ layer is formed thereon by IBAD, for example. The connection portion alignment layer 431 and the connection portion intermediate layer 432 become the connection alignment layer 435.

  At this time, the height of the surfaces of the first and second superconducting layers 140 and 240 and the height of the surface of the connection orientation layer 435 (for example, the surface of the connection portion intermediate layer 432) are substantially the same. An alignment layer 435 is formed. If the heights are significantly different, the current value of the superconducting connection may decrease. For example, since the thickness of the superconducting connector 300 is about 1 μm, it is effective that the step on the surface on which the superconducting connector 300 is provided is, for example, about 0.1 μm or less.

Then, the mask 450 is removed, and a superconducting layer to be the superconducting connection body 300 is formed on the first and second superconducting wires 100 and 200 and the connection orientation layer 435.
In this way, the superconducting wire 40 according to the present embodiment is obtained.

The superconducting wire 40 according to the present embodiment thus connected has a connection resistance of 1.0 × 10 ⁻¹² Ω which is much smaller than the connection resistance value of 1.0 × 10 ⁻⁹ Ω, which is the lowest resistance according to the prior art. realizable.

At this time, the same material as the superconducting layers 140 and 240 of the first and second superconducting wires 100 and 200 can be used for the superconducting layer to be the superconducting connector 300.
However, also in the superconducting wire 40 according to the present embodiment, the superconducting layer of the first and second superconducting wires 100 and 200 is included in the superconducting layer to be the superconducting connector 300, as in the superconducting wire 10 of the first embodiment. It is desirable to use a different type of material than 140 and 240.

  That is, it is desirable that superconducting connector 300 includes an element different from the element included in first superconducting layer 140 of first superconducting wire 100. In addition, it is desirable that superconducting connector 300 includes an element different from the element included in second superconducting layer 240 of second superconducting wire 200.

  For example, lanthanoids that express superconductivity include La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. In addition, as a material that develops superconductivity, a material containing yttrium (Y) can be given. Therefore, the superconducting connector 300 is different from the elements contained in the first and second superconducting layers 140 and 240, La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y. At least one selected from the group consisting of:

  Note that, in the first and second superconducting layers 140 and 240, the superconducting current is formed in a state obtained mainly in a direction parallel to the layer surfaces of the first and second superconducting layers 140 and 240. The critical current density of the superconducting current flowing toward the superconducting connector 300 is considered to be as low as about 1/100 to 1/1000 of the superconducting current obtained in the direction parallel to the layer surface. However, this decrease in superconducting current can be avoided by widening the connection area of the superconducting connector 300.

  For example, the layer thickness of the first and second superconducting layers 140 and 240 is, for example, 0.3 μm to 10 μm. At this time, when the widths of the first and second superconducting wires 100 and 200 are the same as the width of the superconducting connection body, the length of the superconducting connection body 300 in the extending direction is 100 to 1000 times or more of this film thickness, that is, If the length of the superconducting connector 300 is 0.3 mm to 10 mm or more, the problem of a decrease in the allowable amount of superconducting current can be solved.

  The thickness of the superconducting layer currently used is about 1 μm, and it is considered that a current in the direction perpendicular to the layer surface of the superconducting layer can obtain a superconducting current about 1/100 of the current in the parallel direction. Therefore, in this case, the length of the region where the superconducting connector 300 overlaps with the first and second superconducting wires 100 and 200 is 100 μm. However, since foreign matter and the like are also present on the surface of the superconducting layer, the contact area when viewed microscopically is 1 of the area of the region where the superconducting connector 300 overlaps the first and second superconducting wires 100 and 200. It is expected to be about / 2 to 1/10. Therefore, the length of the region where the superconducting connector 300 overlaps the first and second superconducting wires 100 and 200 can be 0.2 mm to 1 mm or more. That is, the length of the region where the superconducting connector 300 overlaps the first and second superconducting wires 100 and 200 is desirably 1 mm or more.

  For example, when the length of the region where the superconducting connector 300 overlaps the first and second superconducting wires 100 and 200 is 1 mm, the connection is poor (for example, the concavity and convexity of the connecting surface is large, and the connecting surface is soiled). In other cases, the current flowing through the first and second superconducting wires 100 and 200 and the superconducting connector 300 can be 5 A or more per 1 cm of the width of the first and second superconducting wires 100 and 200.

  In addition, for example, when the length of the region where the superconducting connection body 300 overlaps the first and second superconducting wires 100 and 200 is 1 mm, a high-quality connection (for example, the unevenness of the connection surface is small, the connection surface is soiled) The current flowing through the first and second superconducting wires 100 and 200 and the superconducting connector 300 can be 30 A or more per 1 cm of the width of the first and second superconducting wires 100 and 200.

(Second embodiment)
Guides 2C and 2D made of Hastelloy-C are attached to the respective ends 2A and 2B of the first and second superconducting wires 100 and 200 having a length of about 50 cm.
In the first and second superconducting wires 100 and 200, Hastelloy-C layers 130 and 230 having no orientation are provided on a base material 120 and 220 such as a metal tape, and a film is formed thereon by an IBAD method. Orientation layers 131 and 231 composed of ZrO ₂ layers containing 8 mol% Y ₂ O ₃ are provided, and intermediate layers 132 and 232 composed of CeO ₂ layers formed by the PLD method are provided thereon. Superconducting layers 140 and 240 made of a YBCO layer are provided thereon.

    The thickness of the first and second superconducting wires 100 and 200 is 0.1 mm, the thickness of the Hastelloy-C layer (130, 230) is about 0.1 to 0.5 mm, and the thickness of the alignment layers 131 and 231 is The thickness of the intermediate layers 132 and 232 is about 0.2 μm, and the thickness of the superconducting layers 140 and 240 is about 1 μm.

  Then, the steps are measured with the ends 2A, 2B attached to the guides 2C, 2D made of Hastelloy-C that fixes the ends 2A, 2B so as not to move. Based on the result, the step adjusting material 420 provided with a step so that the step at one end 1A, 1B is 0.1 μm or less is selected, and this is used as the back surface of the one end 1A, 1B (first and second superconducting layers 140, It is attached to the surface opposite to 240). Hereinafter, this connection portion is referred to as a processed portion 2X.

A slit (mask 450) having a sufficient thickness that is not completely cut off during ion milling is provided on the surface of the workpiece 2X, and is placed in an ion milling chamber. The gas in the chamber is reduced to 1.0 × 10 ⁻³ Pa using Ar as the gas. First, ion milling is performed for 20 minutes from the direction of an incident angle (angle from the normal of the processed surface) with an acceleration voltage of 300 V, and then from the direction of an incident angle of 0 degree with an acceleration voltage of 200 V. Perform ion milling for 60 minutes. In the above ion milling, it is known from another experiment that the milling speed is 20 nm / min under the initial stage conditions and 10 nm / min under the subsequent stage conditions. Therefore, the total depth of the portion dug by the above ion milling is approximately 1,000 nm.

Next, the processed part 2X is placed in the IBAD film forming chamber with a slit. Then, the incidence angle of Ar ⁺ ions is set to 35 degrees, which is a commonly used angle, and the YSZ layer is formed with an acceleration voltage of 200 eV. In addition, the to-be-processed part 2X is not cooled. The temperature of the workpiece 2X is estimated to be 70 ° C. to 100 ° C. due to overheating by argon ion irradiation. During film formation, the total pressure is reduced to 4.0 × 10 ⁻² Pa. The film thickness of the YSZ film is 0.50 μm.

Thereafter, a CeO ₂ layer is formed on the workpiece 2X by the PLD method. At this time, the temperature of the processed part 2X is set to 765 ° C., the oxygen partial pressure is set to 20 mTorr, and film formation is performed with a Kr—F excimer laser so that the film thickness becomes 0.50 μm. Thus, first at one end 2A, 2B, the surface of the second superconducting layer 140 and 240, and the surface of the CeO ₂ layer is approximately equal height. This height can be confirmed by a step gauge.

Thereafter, the part 2X to be processed is placed in another PLD method chamber, and a film to be the superconducting connection body 300 is formed using the Kr-F laser. At this time, the temperature of the processed part 2X is set to 775 ° C., the oxygen partial pressure is set to 300 mTorr, and a target made of YBa ₂ Cu ₃ O ₆ is used to form a film at an energy density of 1.8 J / cm ⁻² . Then, film formation is performed while monitoring the film thickness with a detector in the chamber so that the film thickness of the superconducting film becomes about 1 μm.

Thereafter, the part to be processed 1X is subjected to oxygen annealing in a 100% oxygen gas at 450 ° C. for 1 hour in an electric furnace to obtain a YBCO layer which is a superconducting film.
After cooling the electric furnace, the workpiece 2X is taken out from the electric furnace, and the superconducting wire 42 (not shown) of this embodiment is obtained.

Then, the superconducting wire 42 is cooled in liquid nitrogen inside the magnetic shield, a magnetic field is applied to the superconducting wire 42, the current is maintained in the permanent current mode, and the magnetic flux of the superconducting wire 42 connected by the Hall element after a certain time. To determine the connection resistance value. The initial current value is 12 A, and the resistance of the superconducting connection is 1.6 × 10 ⁻¹³ Ω. In addition, since the width of the superconducting wire 42 is 4 mm, the superconducting wire 41 according to the present embodiment corresponds to obtaining a critical current value of 30 A per 1 cm width.

(Third embodiment)
A guide 3C and a guide 3D made of Hastelloy-C are respectively attached to one ends 3A and 3B of the first and second superconducting wires 100 and 200 having a length of about 50 cm.
In the first and second superconducting wires 100 and 200, Hastelloy-C layers 130 and 131 having no orientation are provided on a base material 120 and 220 such as a metal tape, and a film is formed thereon by the IBAD method. The alignment layers 131 and 231 made of Ga ₂ Zr ₂ O ₇ are provided, the intermediate layers 132 and 232 made of CeO ₂ formed by the PLD method are provided thereon, and the YBCO film is further provided thereon. First and second superconducting layers 140 and 240 are provided.

  The total thickness of the first and second superconducting wires 100 and 200 is about 0.1 mm, the thickness of the alignment layers 131 and 231 is about 1 μm, the thickness of the intermediate layers 132 and 232 is about 0.2 μm, The thicknesses of the first and second superconducting layers 140 and 240 are about 1 μm.

  Then, the steps are measured with the ends 3A, 3B attached to the guides 3C, 3D made of Hastelloy-C that fixes the ends 3A, 3B so as not to move. Based on the result, a step adjusting material 420 provided with a step so that the step at one end 3A, 3B is 0.1 μm or less is selected, and this is used as the back surface of the one end 3A, 3B (first and second superconducting layers 140, It is attached to the surface opposite to 240). Hereinafter, this connection portion is referred to as a processed portion 3X.

A slit having a sufficient thickness that is not cut off at the time of ion milling is provided on the surface of the workpiece 3X, and is placed in an ion milling chamber. The gas in the chamber is reduced to 1.0 × 10 ⁻³ Pa using Ar as the gas. First, ion milling is performed for 20 minutes from the direction of an incident angle of 50 degrees with an acceleration voltage of 300 V, and then ion milling is performed for 60 minutes from the direction of an incident angle of 0 degrees with an acceleration voltage of 200 V. In the above ion milling, it is known from another experiment that the milling speed is 20 nm / min under the initial stage conditions and 10 nm / min under the subsequent stage conditions. Therefore, the total depth of the portion dug by the ion milling is approximately 1,000 nm.

Next, the processed portion 3X is placed in the IBAD film forming chamber with a slit. Then, the incident angle of Ar ⁺ ions is set to 35 degrees, which is a commonly used angle, and a Ga ₂ Zr ₂ O ₇ layer is formed with an acceleration voltage of 200 eV. The processed part 3X is not cooled. The temperature of the part to be processed 3X is estimated to be 150 ° C. to 200 ° C. due to overheating by argon ion irradiation. During film formation, the total pressure is reduced to 4.0 × 10 ⁻² Pa. The film thickness of the Ga ₂ Zr ₂ O ₇ layer is 0.50 μm.

Thereafter, a CeO ₂ layer is formed on the processed part 3X by the PLD method. At this time, the temperature of the processed part 3X is set to 765 ° C., the oxygen partial pressure is set to 20 mTorr, and the film is formed with a Kr—F excimer laser so that the film thickness becomes 0.50 μm. Thus, first at one end 3A, 3B, the surface of the second superconducting layer 140 and 240, and the surface of the CeO ₂ layer is approximately equal height. This height can be confirmed by a step gauge.

Thereafter, the processed part 3X is placed in another PLD method chamber, and a film to be the superconducting connection body 300 is formed using the Kr-F laser. At this time, the temperature of the processed part 3X is set to 775 ° C., the oxygen partial pressure is set to 300 mTorr, and a target made of YBa ₂ Cu ₃ O ₆ is used to form a film at an energy density of 1.8 J / cm ⁻² . Then, film formation is performed while monitoring the film thickness with a detector in the chamber so that the film thickness of the superconducting film becomes about 1 μm.

Thereafter, the part to be processed 3X is subjected to oxygen annealing in a 100% oxygen gas at 450 ° C. for 1 hour in an electric furnace to obtain a YBCO layer which is a superconducting film.
After cooling the electric furnace, the part to be processed 3X is taken out from the electric furnace, and the superconducting wire 43 of this embodiment is obtained.

Then, the superconducting wire 43 is cooled in liquid nitrogen inside the magnetic shield, a magnetic field is applied to the superconducting wire 43, the current is maintained in the permanent current mode, and the magnetic flux of the superconducting wire 43 connected by the Hall element after a certain time. To determine the connection resistance value. The initial current value is 9 A, and the resistance of the superconducting connection is 1.0 × 10 ⁻¹³ Ω.

(Fourth embodiment)
A guide 3C and a guide 3D made of Hastelloy-C are attached to the respective ends 4A and 4B of the first and second superconducting wires 100 and 200 having a length of about 50 cm.
In the first and second superconducting wires 100 and 200, a seed layer made of Y ₂ O ₃ is provided on a base material 120, 220 made of Ni—W having an alignment layer, and a barrier layer made of YSZ is formed thereon. And the intermediate layers 132 and 232 made of CeO ₂ are provided thereon. These seed layer, barrier layer, and intermediate layers 132 and 232 are all formed by the PLD method. Then, first and second superconducting layers 140 and 240 made of a YBCO film are provided on the intermediate layer.

  The total thickness of the first and second superconducting wires 100 and 200 is about 0.1 mm, the thickness of the intermediate layers 132 and 232 is about 1 μm, and the thickness of the first and second superconducting layers 140 and 240 is about 1 μm.

  Then, the steps are measured with the ends 4A, 4B attached to the guides 3C, 3D made of Hastelloy-C that fixes the ends 4A, 4B so as not to move. Based on the result, a step adjusting material 420 provided with a step so that the step at one end 4A, 4B is 0.1 μm or less is selected, and this is used as the back surface of the one end 4A, 4B (first and second superconducting layers 140, It is attached to the surface opposite to 240). Hereinafter, this connection portion is referred to as a processed portion 4X.

A slit having a sufficient thickness that is not cut off at the time of ion milling is provided on the surface of the workpiece 4X, and is placed in an ion milling chamber. The gas in the chamber is reduced to 1.0 × 10 ⁻³ Pa using Ar as the gas. First, ion milling is performed for 20 minutes from the direction of an incident angle of 50 degrees with an acceleration voltage of 300 V, and then ion milling is performed for 60 minutes from the direction of an incident angle of 0 degrees with an acceleration voltage of 200 V. In the above ion milling, it is known from another experiment that the milling speed is 20 nm / min under the initial stage conditions and 10 nm / min under the subsequent stage conditions. Therefore, the total depth of the portion dug by the above ion milling is approximately 1,000 nm.

Next, the processed portion 4X is placed in the IBAD film forming chamber with a slit. Then, the incident angle of Ar ⁺ ions is set to 35 degrees, which is a commonly used angle, and YSZ film formation is performed with an acceleration voltage of 200 eV. The processed part 4X is not cooled. The temperature of the workpiece 4X is estimated to be 150 ° C. to 200 ° C. due to overheating by argon ion irradiation. During film formation, the total pressure is reduced to 4.0 × 10 ⁻² Pa. The film thickness of the YSZ layer is 0.50 μm.

Thereafter, a CeO ₂ layer is formed on the processed part 4X by the PLD method. At this time, the temperature of the processed part 4X is set to 765 ° C., the oxygen partial pressure is set to 20 mTorr, and the film is formed with a Kr—F excimer laser so that the film thickness becomes 0.50 μm. Thus, first at one end 4A, 4B, and the surface of the second superconducting layer 140 and 240, and the surface of the CeO ₂ layer is approximately equal height. This height can be confirmed by a step gauge.

Thereafter, the part to be processed 4X is put in another PLD method chamber, and a film to be the superconducting connection body 300 is formed using the Kr-F laser. At this time, the temperature of the processed part 3X is set to 775 ° C., the oxygen partial pressure is set to 300 mTorr, and a target made of YBa ₂ Cu ₃ O ₆ is used to form a film at an energy density of 1.8 J / cm ⁻² . Then, film formation is performed while monitoring the film thickness with a detector in the chamber so that the film thickness of the superconducting film becomes about 1 μm.

Thereafter, the part to be processed 4X is subjected to oxygen annealing in a 100% oxygen gas at 450 ° C. for 1 hour in an electric furnace to obtain a YBCO layer which is a superconducting film.
After cooling the electric furnace, the part to be processed 4X is taken out of the electric furnace, and the superconducting wire 44 (not shown) of this embodiment is obtained.

Then, the superconducting wire 44 is cooled in liquid nitrogen inside the magnetic shield, a magnetic field is applied to the superconducting wire 44, the current is maintained in the permanent current mode, and the magnetic flux of the superconducting wire 44 connected by the Hall element after a certain time. To determine the connection resistance value. The initial current value is 9 A, and the resistance of the superconducting connection is 8.6 × 10 ⁻¹³ Ω.
This connection resistance value satisfies 1.0 × 10 ⁻¹² Ω or less required for high-characteristic NMR. Thus, even in a superconducting wire having a superconducting wire layer formed on the RABiTS layer, superconducting connection having a resistance value necessary for the permanent current mode can be performed.

(Fifth embodiment)
A guide 5C and a guide 5D made of Hastelloy-C are respectively attached to one ends 5A and 5B of the first and second superconducting wires 100 and 200 having a length of about 50 cm.

In the first superconducting wire 100, a Hastelloy-C layer 130 having no orientation is provided on a base material 120 such as a metal tape, and is formed of Ga ₂ Zr ₂ O ₇ formed thereon by the IBAD method. An alignment layer 131 is provided, an intermediate layer 132 made of CeO ₂ formed by the PLD method is provided thereon, and a first superconducting layer 140 made of a YBCO film formed by the PLD method is provided thereon. It has been.

  The total thickness of the first superconducting wire 100 is about 0.1 mm, the thickness of the alignment layer 231 is about 1 μm, the thickness of the intermediate layer 132 is about 0.2 μm, and the thickness of the first superconducting layer 140 is The thickness is about 1 μm.

On the other hand, in the second superconducting wire 200, a seed layer made of Y ₂ O ₃ is provided on a base material 220 made of Ni—W having an alignment layer, and a barrier layer made of YSZ is provided thereon, and An intermediate layer 232 made of CeO ₂ is provided thereon. These seed layer, barrier layer, and intermediate layer 232 are all formed by the PLD method. A second superconducting layer 240 made of a YBCO film is provided on the intermediate layer 232.

  The entire thickness of the second superconducting wire 200 is about 0.1 mm, the thickness of the intermediate layer 232 is about 1 μm, and the thickness of the second superconducting layer 240 is about 1 μm.

  Then, the steps are measured with the ends 5A, 5B attached to the guides 5C, 5D made of Hastelloy-C that fixes the ends 5A, 5B so as not to move. Based on the result, a step adjusting material 420 provided with a step so that the step at one end 5A, 5B is 0.1 μm or less is selected, and this is used as the back surface of the one end 5A, 5B (first and second superconducting layers 140, It is attached to the surface opposite to 240). Hereinafter, this connecting portion will be referred to as a processed portion 5X.

A slit having a sufficient thickness that is not cut off at the time of ion milling is provided on the surface of the workpiece 5X, and is placed in an ion milling chamber. The gas in the chamber is reduced to 1.0 × 10 ⁻³ Pa using Ar as the gas. First, ion milling is performed for 20 minutes from the direction of an incident angle of 50 degrees with an acceleration voltage of 300 V, and then ion milling is performed for 60 minutes from the direction of an incident angle of 0 degrees with an acceleration voltage of 200 V. In the above ion milling, it is known from another experiment that the milling speed is 20 nm / min under the initial stage conditions and 10 nm / min under the subsequent stage conditions. Therefore, the total depth of the portion dug by the above ion milling is approximately 1,000 nm.

Next, the processed part 5X is placed in the IBAD film forming chamber with a slit. Then, the incident angle of Ar ⁺ ions is set to 35 degrees, which is a commonly used angle, and a film of Ga ₂ Zr ₂ O ₇ is formed with an acceleration voltage of 200 eV. In addition, the to-be-processed part 5X is not cooled. The temperature of the processed part 5X is estimated to be 150 ° C. to 200 ° C. due to overheating by argon ion irradiation. During film formation, the total pressure is reduced to 4.0 × 10 ⁻² Pa. The film thickness of the Ga ₂ Zr ₂ O ₇ layer is 0.50 μm.

Thereafter, a CeO ₂ layer is formed on the workpiece 5X by the PLD method. At this time, the temperature of the processed part 5X is set to 765 ° C., the oxygen partial pressure is set to 20 mTorr, and the film is formed with a Kr—F excimer laser so that the film thickness becomes 0.50 μm. Thus, first at one end 5A, 5B, the surface of the second superconducting layer 140 and 240, and the surface of the CeO ₂ layer is approximately equal height. This height can be confirmed by a step gauge.

Thereafter, the part to be processed 5X is placed in another PLD method chamber, and a film to be the superconducting connection body 300 is formed using the Kr-F laser. At this time, the temperature of the processed part 3X is set to 775 ° C., the oxygen partial pressure is set to 300 mTorr, and a target made of YBa ₂ Cu ₃ O ₆ is used to form a film at an energy density of 1.8 J / cm ⁻² . Then, film formation is performed while monitoring the film thickness with a detector in the chamber so that the film thickness of the superconducting film becomes about 1 μm.

Thereafter, the part to be processed 5X is subjected to oxygen annealing in a 100% oxygen gas at 450 ° C. for 1 hour in an electric furnace to obtain a YBCO layer which is a superconducting film.
After the electric furnace is cooled, the workpiece 5X is taken out from the electric furnace, and the superconducting wire 45 (not shown) of this embodiment is obtained.

Then, the superconducting wire 45 is cooled in liquid nitrogen inside the magnetic shield, a magnetic field is applied to the superconducting wire 45, the current is maintained in the permanent current mode, and the magnetic flux of the superconducting wire 45 connected by the Hall element after a certain time. To determine the connection resistance value. The initial current value is 11 A, and the resistance of the superconducting connection is 4.2 × 10 ⁻¹³ Ω.

  Thus, the structure and method of this embodiment can also be applied when connecting superconducting wires having different layers on the base of the superconducting layer, and in this case also, the superconducting connection having the resistance value necessary for the permanent current mode is applicable. Can be realized.

(Sixth embodiment)
A guide 6C and a guide 6D made of Hastelloy-C are attached to each of one end of each of ten superconducting wires having a length of about 50 cm (that is, two sets of two). In 10 superconducting wires, a Hastelloy-C layer 130 having no orientation is provided on a base material 120 such as a metal tape, and an 8 mol% Y ₂ O ₃ compound film formed thereon by the IBAD method is provided thereon. An alignment layer made of ZrO ₂ (YSZ) is provided, an intermediate layer made of CeO ₂ formed by the PLD method is provided thereon, and a superconducting layer made of a YBCO film formed by the PLD method thereon Is provided.

  The total thickness of the superconducting wire is about 0.1 mm, the thickness of the alignment layer is about 1 μm, the thickness of the intermediate layer is about 0.2 μm, and the thickness of the superconducting layer is about 1 μm.

  Then, the level difference is measured with one end attached to guides 6C and 6D made of Hastelloy-C that fixes one end of the superconducting wire so that it does not move. Based on the result, the step adjusting material 420 is selected such that the step between the ends is 0.1 μm, 0.2 μm, 0.4 μm, 0.7 μm, and 1.0 μm, and this is used as the back surface of the connection end of the superconducting wire ( Attached to the surface opposite to the superconducting layer). Hereinafter, these five connection portions will be referred to as processed portions 6X1, 6X2, 6X3, 6X4, and 6X5.

A slit having a sufficient thickness not to be cut off at the time of ion milling is provided on the surface of the workpieces 6X1, 6X2, 6X3, 6X4, and 6X5, and placed in an ion milling chamber. The gas in the chamber is reduced to 1.0 × 10 ⁻³ Pa using Ar as the gas. First, ion milling is performed for 20 minutes from the direction of an incident angle of 50 degrees with an acceleration voltage of 300 V, and then ion milling is performed for 60 minutes from the direction of an incident angle of 0 degrees with an acceleration voltage of 200 V. In the above ion milling, it is known from another experiment that the milling speed is 20 nm / min under the initial stage conditions and 10 nm / min under the subsequent stage conditions. Therefore, the total depth of the portion dug by the above ion milling is approximately 1,000 nm.

Next, the processed parts 6X1, 6X2, 6X3, 6X4, and 6X5 are placed in the IBAD film forming chamber with the slits. Then, the incidence angle of Ar ⁺ ions is set to 35 degrees, which is a commonly used angle, and the YSZ layer is formed with an acceleration voltage of 200 eV. Note that the surfaces of the processed parts 6X1, 6X2, 6X3, 6X4, and 6X5 are not cooled. The temperatures of the parts 6X1, 6X2, 6X3, 6X4, and 6X5 are estimated to be 150 ° C. to 200 ° C. due to overheating by argon ion irradiation. During film formation, the total pressure is reduced to 4.0 × 10 ⁻² Pa. The film thickness of the YSZ layer is 0.50 μm.

Thereafter, a CeO ₂ layer is formed on the processed parts 6X1, 6X2, 6X3, 6X4, and 6X5 by the PLD method. At this time, the temperature of the processed parts 6X1, 6X2, 6X3, 6X4, and 6X5 is set to 765 ° C., the oxygen partial pressure is set to 20 mTorr, and the film is formed with a Kr—F excimer laser so that the film thickness becomes 0.50 μm. . Thereby, the surface of the superconducting layer at the connection end and the surface of the CeO ₂ layer have substantially the same height. This height can be confirmed by a step gauge.

Thereafter, the processed parts 6X1, 6X2, 6X3, 6X4, and 6X5 are placed in another PLD method chamber, and a film that becomes the superconducting connection body 300 is formed using the Kr-F laser. At this time, the temperature of the processed parts 6X1, 6X2, 6X3, 6X4, and 6X5 is set to 775 ° C., the oxygen partial pressure is set to 300 mTorr, and a target made of YBa ₂ Cu ₃ O ₆ is used and the energy is 1.8 J / cm ⁻² . Films are formed at a density. Then, film formation is performed while monitoring the film thickness with a detector in the chamber so that the film thickness of the superconducting film becomes about 1 μm.

Thereafter, the parts to be processed 6X1, 6X2, 6X3, 6X4, and 6X5 are subjected to oxygen annealing in a 100% oxygen gas at 450 ° C. for 1 hour in an electric furnace to obtain a YBCO layer that is a superconducting film.
After the electric furnace is cooled, the processed parts 6X1, 6X2, 6X3, 6X4, and 6X5 are taken out of the electric furnace to obtain superconducting wires 46a, 46b, 46c, 46d, and 46e (not shown) of this embodiment.

Then, the superconducting wires 46a, 46b, 46c, 46d, 46e are cooled in liquid nitrogen inside the magnetic shield, a magnetic field is applied to the superconducting wires 46a, 46b, 46c, 46d, 46e, and the current is maintained in the permanent current mode. Then, the connection resistance value is obtained by measuring the magnetic flux of the superconducting wire connected by the Hall element after a certain time. The initial current value of the superconducting wires 46a, 46b, 46c, 46d, and 46e is 14A at the maximum, and the resistance of the superconducting connection portions of the superconducting wires 46a, 46b, 46c, 46d, and 46e is 1.8 × 10 ^{− 13} Ω, 2.8 × 10 ⁻¹³ Ω, 7.0 × 10 ⁻¹³ Ω, 1.3 × 10 ⁻¹² Ω, and 8.8 × 10 ⁻¹² Ω.

  Thus, the allowable current value of the superconducting connection portion increases as the level difference between the connection ends decreases. Accordingly, it is desirable that the level difference is small, for example, 0.5 μm or less. Moreover, it is desirable to make it 50% or less of the thickness of the superconducting layer of the superconducting wire to be connected.

However, even in the superconducting wire 46e having the largest step of 1.0 μm, the resistance value is 8.8 × 10 ⁻¹² Ω, which is an extremely low resistance value compared to the conventional one.

(Fifth embodiment)
FIG. 11 is a flowchart illustrating the method for manufacturing a superconducting wire according to the fifth embodiment of the invention.
As shown in FIG. 11, in the method for manufacturing a superconducting wire according to the fifth embodiment of the present invention, the c-axis surface 111 of the first superconducting wire 100, the c-axis surface 211 of the second superconducting wire 200, A superconducting connection body 300 that electrically connects the first superconducting wire 100 and the second superconducting wire 200 is formed on the substrate (step S10).
Thereby, the manufacturing method of a superconducting wire which connects a superconducting wire with the superconductor which can make an allowable current value large can be provided.

FIG. 12 is a flowchart illustrating another method for manufacturing a superconducting wire according to the fifth embodiment of the invention.
As shown in FIG. 12, in another superconducting wire manufacturing method according to the fifth embodiment of the present invention, before the formation of the superconducting connection body (step S <b> 10), first, the first superconducting wire 100 of the first superconducting wire 100. The first superconducting layer 140 and the second superconducting layer 240 of the second superconducting wire 200 are retracted from the surface where the first superconducting wire 100 and the second superconducting wire 200 face each other (step S8).

  Then, an alignment layer (connection alignment layer 435) is formed on the first superconducting wire 100 where the first superconducting layer 240 has receded and the second superconducting wire 200 where the second superconducting layer 240 has receded. (Step S9).

  Thereby, the orientation of the superconducting connector 300 can be increased, and the connection resistance can be further reduced.

FIG. 13 is a flowchart illustrating another superconducting wire manufacturing method according to the fifth embodiment of the invention.
As shown in FIG. 13, in another method of manufacturing a superconducting wire according to the fifth embodiment of the present invention, the first superconducting wire 100 is formed before the formation of the superconducting connection (step S <b> 10). A step adjusting material 420 for adjusting a step between the first main surface on the layer 140 side and the second main surface on the second superconducting layer 240 side of the second superconducting wire 200 is opposite to the first main surface. It is provided on at least one of the surface of the first superconducting wire 100 on the side and the surface of the second superconducting wire 200 on the side opposite to the second main surface (step S7).

At this time, the step adjusting member 420 includes a first main surface of the first superconducting wire 100 on the first superconducting layer 140 side and a second main surface of the second superconducting wire 200 on the second superconducting layer 240 side. The level difference can be adjusted to be reduced.
Thereby, the step difference between the first main surface of the first superconducting wire 100 on the first superconducting layer 140 side and the second main surface of the second superconducting wire 200 on the second superconducting layer 240 side can be reduced. It is possible to further increase the allowable amount of superconducting current in the connection portion.

  In the above description, the first main surface of the first superconducting wire 100 on the first superconducting layer 140 side and the second main surface of the second superconducting wire 200 on the second superconducting layer 240 side are strictly in the same plane. The first main surface of the first superconducting wire 100 on the first superconducting layer 140 side and the step difference between the second main surface of the second superconducting wire 200 on the second superconducting layer 240 side. Should be reduced. This step can be, for example, 1 μm or less.

  Further, in the method of manufacturing a superconducting wire according to the present embodiment, as illustrated in FIG. 5, one end of the first superconducting wire 100 is connected to the extending direction of the second superconducting wire 200 before the superconducting connector 300 is formed. Can be arranged adjacent to one end of the second superconducting wire 200 in a direction perpendicular to the first superconducting wire 200. This makes it easier to reduce the connection resistance.

  The superconducting wire according to the embodiment of the present invention and the manufacturing method thereof can be applied to superconducting wires of various materials such as yttrium-based and yttrium-based superconductors, which are oxide superconductors.

  In addition, the superconducting wire and the manufacturing method thereof according to the embodiment of the present invention include, for example, a PLD method, a metal organic chemical vapor deposition (MOCVD) method, an electron beam (EB) method, a trinization method, and the like. It can be applied to superconducting wires produced by various methods such as metal organic deposition using trifluoroacetates (TFA-MOD) using fluoroacetate.

  In the superconducting wire and the manufacturing method thereof according to the embodiment of the present invention, various methods such as a PLD method, an MOCVD method, an EB method, and a TFA-MOD method can be used to form the superconducting connection body 300. .

As described above, according to the embodiment of the present invention, in a superconducting wire having a biaxially oriented structure, a superconducting current flow can be obtained by bonding a large area in the c-axis direction, which is conventionally considered difficult to obtain current. Therefore, a low resistance value of 10 ⁻¹² Ω or less necessary for NMR can be realized, and a permanent current mode can be realized. Realization of 1 GHz NMR is expected to contribute to the future society, including contribution to the field of drug discovery through the development of biotechnology.

  In addition, this connection technique is a technique that enables superconducting wires that are relatively short and have stable characteristics to be joined together to make a long wire. Solar power generation is considered to occupy an important position when fossil fuels are depleted, and the clear sky rate is as high as 95%. Installation and large power transmission will play an important role in resolving energy shortages.

The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. For example, regarding the specific configuration of each element constituting the superconducting wire and the manufacturing method thereof, as long as a person skilled in the art can implement the present invention in a similar manner by appropriately selecting from a known range, the same effect can be obtained. Are included within the scope of the present invention.
Moreover, what combined any two or more elements of each specific example in the technically possible range is also included in the scope of the present invention as long as the gist of the present invention is included.

  In addition, based on the superconducting wire and the manufacturing method thereof described above as the embodiment of the present invention, all superconducting wires and methods of manufacturing the superconducting wire that can be implemented by those skilled in the art appropriately include the gist of the present invention. As long as it belongs to the scope of the present invention.

  In addition, in the category of the idea of the present invention, those skilled in the art can conceive of various changes and modifications, and it is understood that these changes and modifications also belong to the scope of the present invention. .

It is a schematic diagram which illustrates the composition of the superconducting wire concerning the 1st embodiment of the present invention. It is a typical sectional view which illustrates the composition of the superconducting wire concerning the 1st embodiment of the present invention. It is typical sectional drawing which illustrates the structure of the superconducting wire of a comparative example. FIG. 5 is a schematic plan view illustrating the configuration of a modification example of the superconducting wire according to the first embodiment of the present invention. FIG. 5 is a schematic plan view illustrating the configuration of a modification example of the superconducting wire according to the first embodiment of the present invention. It is a schematic diagram which illustrates the structure of the superconducting wire which concerns on the 1st Example of this invention. It is a typical sectional view which illustrates the composition of the superconducting wire concerning the 2nd embodiment of the present invention. It is typical sectional drawing which illustrates the structure of the superconducting wire which concerns on the 3rd Embodiment of this invention. It is a schematic diagram which illustrates the structure of the superconducting wire which concerns on the 4th Embodiment of this invention. It is process order typical sectional drawing which illustrates the manufacturing method of the superconducting wire which concerns on the 4th Embodiment of this invention. It is a flowchart figure which illustrates the manufacturing method of the superconducting wire which concerns on the 5th Embodiment of this invention. It is a flowchart figure which illustrates the manufacturing method of another superconducting wire which concerns on the 5th Embodiment of this invention. It is a flowchart figure which illustrates the manufacturing method of another superconducting wire which concerns on the 5th Embodiment of this invention.

Explanation of symbols

10, 10a to 10i, 11, 20, 30, 40, 42, 43, 44, 45, 46a to e, 91 to 93 Superconducting wire 100 First superconducting wire 110 c-axis 111 c-axis surface 120 First base material 130 Hastelloy -C layer 131 orientation layer 132 intermediate layer 140 first superconducting layer 200 second superconducting wire 210 c-axis 211 c-axis surface 220 second base material 230 Hastelloy-C layer 231 orientation layer 232 intermediate layer 240 second superconducting layer 300 superconducting connection Body 310 c-axis 410 Embedding material 420 Step adjusting material 431 Connection portion alignment layer 432 Connection portion intermediate layer 435 Connection alignment layer 450 Mask 510, 520, 530 Connection material 531 Filler a1 to a5 Arrow

Claims (18)

a first superconducting wire having a first superconducting layer having a c-axis plane as a main surface;
A second superconducting wire juxtaposed with the first superconductor and having a second superconducting layer having a c-axis plane as a main surface;
A superconducting connection comprising a superconductor connected to the main surface of the first superconducting layer and the main surface of the second superconducting layer, and electrically connecting the first superconducting layer and the second superconducting layer. Body,
A superconducting wire characterized by comprising The area of the portion where the first superconducting layer and the superconducting connector are connected is at least 100 times the cross-sectional area of the first superconducting layer in a plane perpendicular to the extending direction of the first superconducting wire. ,
The area of the portion where the second superconducting layer and the superconducting connector are connected is at least 100 times the cross-sectional area of the second superconducting layer in a plane perpendicular to the extending direction of the second superconducting wire. The superconducting wire according to claim 1.   The first and second superconducting wires are juxtaposed such that a side surface parallel to the extending direction of the first superconducting wire and a side surface parallel to the extending direction of the second superconducting wire face each other. The superconducting wire according to claim 1 or 2, wherein:   4. The superconducting wire according to claim 3, wherein the length of the first superconducting wire and the second superconducting wire facing each other is 10 times or more the line width of the first superconducting wire and the second superconducting wire. .   The current flowing through the first superconducting wire, the superconducting connector, and the second superconducting wire is 5 A or more per 1 cm of the width of the first superconducting wire and the width of the second superconducting wire. The superconducting wire according to any one of 1 to 4.   The current flowing through the first superconducting wire, the superconducting connector, and the second superconducting wire is 30 A or more per 1 cm of the width of the first superconducting wire and the width of the second superconducting wire. The superconducting wire according to any one of 1 to 4.   The superconducting wire according to claim 1, further comprising an embedding material embedded in a gap between the first superconducting wire and the second superconducting wire.   At least one of the first superconducting wire and the second superconducting wire is provided on a surface opposite to the surface facing the superconducting connector, and the main surface of the first superconducting wire and the second superconducting wire. The superconducting wire according to any one of claims 1 to 7, further comprising a step-adjusting material for adjusting the step.   The first superconducting layer and the second superconducting layer are receded from a surface where the first superconducting wire and the second superconducting wire are opposed to each other, and the first superconducting layer is a part of the receding portion of the first superconducting layer. 9. The semiconductor device according to claim 1, further comprising an alignment layer provided between the first superconducting wire and the second superconducting wire in a portion where the second superconducting layer has receded, and the superconducting connector. The superconducting wire described in 1.   The superconducting wire according to claim 9, wherein the portion where the first superconducting layer is retreated and the portion where the second superconducting layer is retreated are formed by etching.   The superconducting wire according to any one of claims 1 to 10, wherein the first superconducting wire and the second superconducting wire contain an oriented non-superconducting oxide.   The superconducting wire according to any one of claims 1 to 11, wherein the superconducting connector includes an element different from the element included in the first superconducting layer.   The superconducting wire according to any one of claims 1 to 12, wherein the superconducting connector includes an element different from the element included in the second superconducting layer.   The superconducting wire according to any one of claims 1 to 13, wherein a thickness of the superconducting connection body is 0.5 µm or more.   The main surface of the first superconducting wire having the first superconducting layer having the c-axis surface as the main surface, and the main surface of the second superconducting wire having the second superconducting layer having the c-axis surface as the main surface. And forming a superconducting connection body made of a superconductor that electrically connects the first superconducting wire and the second superconducting wire. Before forming the superconducting connection,
Retreating the first superconducting layer and the second superconducting layer from the surface where the first superconducting wire and the second superconducting wire face each other;
16. The alignment layer according to claim 15, wherein an alignment layer is formed on the first superconducting wire where the first superconducting layer has receded and the second superconducting wire where the second superconducting layer has receded. Manufacturing method of superconducting wire. Before forming the superconducting connection,
A step adjusting material for adjusting a step between the main surface of the first superconducting layer and the main surface of the second superconducting layer; a surface of the first superconducting wire on the side opposite to the main surface; and 17. The method of manufacturing a superconducting wire according to claim 15, wherein the superconducting wire is provided on at least one of the surface surfaces of the second superconducting wire opposite to the main surface. Before forming the superconducting connection,
The first and second superconducting wires are juxtaposed such that a side surface parallel to the extending direction of the first superconducting wire and a side surface parallel to the extending direction of the second superconducting wire face each other. The method for producing a superconducting wire according to any one of claims 15 to 17, characterized in that:

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