The present invention is intended to increase the critical current density of a wire rod having a shape with good symmetry such as a round wire or a square wire by making use of mechanical milling method. The production method of the present invention for the MgB.sub.2 superconducting wire rod comprises a mixing process of preparing a powder by adding a solid organic compound to a magnesium powder and a boron powder and then applying an impact to the powder to prepare a mixture of the powder in which boron particles are dispersed inside magnesium particles, a filling process of filling a metal tube with the mixture, an elongation process of elongating the metal tube filled with the mixture and a heat treatment process of heat-treating the metal tube to synthesize MgB.sub.2.

Provided is an MgB.sub.2 superconductive thin film wire material allowing for lower costs while maintaining superconductive properties that are equal to or greater than those of the MgB.sub.2 superconductive thin film wire material of prior art, and to provide a production method for the superconductive thin film wire material. The MgB.sub.2 superconductive thin film wire material according to the present invention is a superconductive wire material comprising an MgB.sub.2 thin film formed over an elongated metal base material, characterized in that the MgB.sub.2 thin film exhibits a critical temperature of 30 K or higher, and has a microscopic organization wherein MgB.sub.2 columnar crystal grains stand densely packed on the surface of the elongated metal base material, and a layer of Mg oxide is formed in such a manner as to surround the MgB.sub.2 columnar crystal grains in the grain boundary regions of the MgB.sub.2 columnar crystal grains.

The present disclosure relates to a superconductor including magnesium diboride and a production method therefor. A superconductor having a high critical current density at a certain temperature and under a certain magnetic field may be obtained by doping magnesium diboride with liquid chloroform during the production of the superconductor.

A superconducting wire connector includes superconducting wires and a sintered body containing MgB.sub.2. The superconducting wires are connected by the sintered body. At least one of the superconducting wires includes a superconducting core having a first outer surface. The sintered body is in contact with the first outer surface. A method of connecting superconducting wires by a sintered body containing MgB.sub.2 includes exposing a superconducting core of at least one of the superconducting wires by removing a portion, positioned in the middle in a longitudinal direction of the at least one of the superconducting wires, of a metal sheath disposed around the superconducting core, disposing the at least one of the superconducting wires through a container, filling the container with a raw material of MgB.sub.2, and forming the sintered body being in contact with an outer surface of the superconducting core by sintering the raw material filled in the container.

An object of the invention is to provide: an MgB.sub.2 superconducting thin-film wire that exhibits excellent J.sub.c characteristics even under a 20 K magnetic field; and a method for producing thereof. The MgB.sub.2 superconducting thin-film wire includes a long substrate and an MgB.sub.2 thin film formed on the long substrate. The MgB.sub.2 thin film has a microtexture such that MgB.sub.2 columnar crystal grains stand densely together on the surface of the long substrate, and has T.sub.c of 30 K or higher. In grain boundary regions of the MgB.sub.2 columnar crystal grains, a predetermined transition metal element is dispersed and segregated. The predetermined transition metal element is an element having a body-centered cubic lattice structure.

The present invention addresses the problem of providing a wire material capable of ensuring high critical current density, regardless of the cross-sectional shape thereof. This super-conducting wire material is equipped with an MgB.sub.2 filament, the number density of cavities having a major axis of 10 m or higher in a longitudinal cross-section of the superconducting wire material is in the range of 5-500 mm.sup.2, and the average value of the angle formed between the major axis of the cavities and the axis of the wire material is 60 degrees or more.

An MgB.sub.2 superconducting wire includes a core containing MgB.sub.2 and a metal sheath which surrounds the core. The core includes at least a first MgB.sub.2 core positioned on the center side, and a second MgB.sub.2 core positioned outside the first MgB.sub.2 core, and the density of the second MgB.sub.2 core is lower than the density of the first MgB.sub.2 core.

There is provided a method of manufacturing a continuous wire comprising forming a strip formed from at least one metallic material into a channel, placing at least one powder into the channel and sealing edges of the channel together to produce a wire, wherein the method further comprises mixing the powder with a carrier liquid to create a slurry and placing the slurry into the channel. The carrier liquid is chemically inert with respect to the at least one powder.

A method of manufacturing a superconducting tape includes forming a slurry of superconducting material, forming a slurry of sacrificial material, extruding the slurries of superconducting and sacrificial materials as interdigitated stripes onto a substrate, and removing the sacrificial material to form superconducting filaments.

The present invention addresses a problem of providing an MgB2 wire material having a small reversible bending radius, a superconducting coil using the same, and an MRI without lowering a critical current value and a critical current density of the MgB2 wire material to an extreme. To solve the problem, provided are a superconducting wire having a plurality of MgB2 strands and a first base metal, a superconducting coil using the same, and an MRI, the superconducting wire being characterized in that in a cross section orthogonal to a wire longitudinal direction, a center point of an area surrounded by the plurality of MgB2 strands and a center axis of a cross section of the superconducting wire are disposed in separated positions.