Abstract: A process for controlling an oxygen content of a non-superconductive or superconductive oxide is provided, in which a beam of particles such as ions, electrons or neutrons or an electromagnetic radiation is applied to the non-superconductive or superconductive oxide of a perovskite type such as YBa.sub.2 Cu.sub.3 O.sub.7-x, thereby increasing or reducing the oxygen content of the oxide at the sites of oxygen in the crystal lattice of the oxide. Furthermore, a superconductive device such as a superconductive magnet, superconductive power transmission wire, superconductive transformer, superconductive shield, permanent current switch and electronic element is made by utilizing the process for controlling the oxygen concentration of the superconductive oxide.

Abstract: In a superconducting switching device including a switching member comprising a superconducting wire, and a magnetic field generation section for controlling superconducting-normal conducting transition caused in the switching member, the switching member comprises an oxide superconductor having a high critical temperature and having a large electric resistivity value under the normal conductive state.

Abstract: An aluminum-stabilized superconducting wire comprises an aluminum member, a copper member, and a first diffusion barrier layer formed between the aluminum member and the copper member. The copper member contains a plurality of bundles each having a multiplicity of fine filaments of Nb.sub.3 Sn embedded in a copper alloy and a second diffusion barrier layer surrounding the copper alloy. Preferably, the ratio m in the cross-sectional areas between the first diffusion barrier layer and the aluminum member is selected to meet the condition of 0.03.ltoreq.m<3. The aluminum member is disposed at the central portion of the superconducting wire.

Abstract: A method of producing a composite material of and Nb or V used for a superconductive wire comprises vacuum - melting two kinds of raw materials, 70 wt % Cu and 30 wt % Nb or V to form a melt; scattering the melt by a rotating disc to form a plurality of fine droplets each of which includes Cu and Nb or V at substantially the same compounding rate as the raw materials; and cooling rapidly the fine droplets by spraying an inert gas onto the scattering droplets thereby providing particulate bodies each of which dendrites of Nb or V are precipitated in Cu. The fine particles are compression - molded to form a molded product. The molded product is sintered to form an ingot in which the dendrites of Nb or V are dispersed homogeneously in the Cu base. The ingot is used for producing a superconductive wire, namely, it is subjected to cold rolling to reduce its sectional area, coating with Su or Ga, and diffusion heat-treating the wire to form Nb.sub.3 Sn or V.sub.

Abstract: A superconductive magnet device comprising a coil assembly having a plurality of coil sections stacked along a center axis of the coil assembly, each of the coil sections being formed by winding a composite superconductive wire, which exhibits different superconductivities in one direction to another direction perpendicular to the one direction in a cross section of the wire, in layers in a direction perpendicular to the center axis, wherein the critical current density in a direction parallel to the center axis in the innermost layer of at least a central one of the coil sections is larger than the critical current density in a circumferential direction of the coil assembly. The present superconductive magnet device can withstand quenching of the superconductive state at a higher magnetic field than conventional ones.