A precursor for Nb.sub.3Sn single-core superconducting wire includes a Sn-based wire rod, a first Cu-based tube covering an outer circumferential surface of the Sn-based wire rod, an Nb-based tube covering an outer surface of the first Cu-based tube, and a second Cu-based tube covering an outer surface of the Nb-based tube. The Sn-based wire rod contains a matrix phase and at least one kind of hard phases that is harder than the matrix phase. In a cross section parallel to a longitudinal direction of the precursor for Nb.sub.3Sn single-core superconducting wire, a maximum dimension of the hard phases in a width direction perpendicular to the longitudinal direction is 50% or less of a minimum dimension in the width direction of the Sn-based wire rod and/or is equal to or smaller than a minimum thickness in the width direction of the Nb-based tube.

A method for manufacturing a superconductor is described. A metal assembly precursor can be formed within a hollow copper support element. Forming the metal assembly precursor within a hollow copper support element by positioning a plurality of conductor elements about a core including Sn to provide a first plurality of inner interstitial spaces between the plurality of conductor elements between the core and conductor elements and a second plurality of outer interstitial spaces between the hollow copper support element and the core, the plurality of conductor elements including unreacted Nb. The metal assembly precursor can be reduced via cold drawing to produce a reduced metal assembly. The reduced metal assembly can be reaction heat treated so that the unreacted Nb undergoes a phase transformation to a reacted superconductor.

A method for the production of a superconducting wire (20) uses a monofilament (1) having a powder core (3) that contains at least Sn and Cu, an inner tube (2), made of Nb or an alloy containing Nb, that encloses the powder core (3), and an outer tube (4) in which the inner tube (2) is arranged. The outer side of the inner tube (2) is in contact with the inner side of the outer tube (4) and the outer tube (4) is produced from Nb or from an alloy containing Nb. The outer tube is disposed in a cladding tube. The superconducting current carrying capacity of the superconducting wire is thereby improved.

In various embodiments, superconducting wires incorporate diffusion barriers composed of Nb alloys or Nb—Ta alloys that resist internal diffusion and provide superior mechanical strength to the wires.

In a method for coating a base body, a first target and a second target are arranged in a vacuum chamber. A base body to be coated is arranged in the vacuum chamber is heated to a coating temperature of less than 600° C. During sputtering with sputter gas ions, first target particles are liberated from the first target and second target particles are liberated from the second target and are deposited as coating particles on the base body. A first sputter rate is specified for the first target and a second sputter rate is specified for the second target such that, during the sputtering process, the coating is generated as an A15 phase with an intended stoichiometric ratio of the first target particles to the second target particles. A functional element has a base body and a coating of Nb.sub.3Sn applied directly on the surface of the base body.

In various embodiments, superconducting wires incorporate diffusion barriers composed of Ta alloys that resist internal diffusion and provide superior mechanical strength to the wires.

In the production of an internal-tin-processed Nb.sub.3Sn superconducting wire, the present invention provides a Nb.sub.3Sn superconducting wire that is abundant in functionality, such as, the promotion of formation of a Nb.sub.3Sn layer, the mechanical strength of the superconducting filament (and an increase in interface resistance), the higher critical temperature (magnetic field), and the grain size reduction, and a method for producing it. A method for producing a Nb.sub.3Sn superconducting wire according to an embodiment of the present invention includes a step of providing a bar 10 that has a Sn insertion hole 12 provided in a central portion of the bar 10 and a plurality of Nb insertion holes 14 provided discretely along an outer peripheral surface of the Sn insertion hole 12, and that has an alloy composition being Cu-xZn-yM (x: 0.1 to 40 mass %, M=Ge, Ga, Mg, or Al, provided that, for Mg, x: 0 to 40 mass %), a step of mounting an alloy bar with an alloy composition of Sn-zQ (Q=Ti, Zr, or Hf) into the Sn insertion hole 12 and inserting Nb cores into the Nb insertion holes 14, a step of subjecting the bar 10 to diameter reduction processing to fabricate a Cu-xZn-yM/Nb/Sn-zQ composite multicore wire with a prescribed outer diameter, and a step of subjecting the composite multicore wire to Nb.sub.3Sn phase generation heat treatment.

A method for manufacturing a superconductor is described. A metal assembly precursor can be formed within a hollow copper support element. Forming the metal assembly precursor within a hollow copper support element by positioning a plurality of conductor elements about a core including Sn to provide a first plurality of inner interstitial spaces between the plurality of conductor elements between the core and conductor elements and a second plurality of outer interstitial spaces between the hollow copper support element and the core, the plurality of conductor elements including unreacted Nb. The metal assembly precursor can be reduced via cold drawing to produce a reduced metal assembly. The reduced metal assembly can be reaction heat treated so that the unreacted Nb undergoes a phase transformation to a reacted superconductor.

Methods of forming semiconductor-superconductor hybrid devices with a horizontally-confined channel are described. An example method includes forming a first isolated semiconductor heterostructure and a second isolated semiconductor heterostructure. The method further includes forming a left gate adjacent to a first side of each of the first isolated semiconductor heterostructure and the second isolated semiconductor heterostructure. The method further includes forming a right gate adjacent to a second side, opposite to the first side, of each of the first isolated semiconductor heterostructure and the second isolated semiconductor heterostructure, where a top surface of each of the left gate and the right gate is offset vertically from a selected surface of each of the first isolated semiconductor heterostructure and the second isolated semiconductor heterostructure by a predetermined offset amount. The method further includes forming a superconducting layer over each of the first isolated semiconductor heterostructure and the second isolated semiconductor heterostructure.

Provided are a Sn—Ti alloy powder for a superconducting wire, the Sn—Ti alloy powder making it possible to improve superconducting characteristics by minimizing the size of Sn—Ti particles dispersed in a Sn-based alloy, a method for preparing the same, and a method for manufacturing a superconducting wire using the same, wherein a Sn—Ti alloy is melted to produce a Sn—Ti intermetallic compound having an average particle size of 3 μm or less, and a content of Ti in the entire alloy is 0.5 wt % to 3 wt %, and the method of preparing the Sn—Ti alloy powder for a superconducting wire includes: a Sn—Ti alloy melting step of melting a Sn—Ti alloy or a Sn—Ti alloy processed material; and a Sn—Ti alloy powder formation step of spraying and solidifying a molten Sn—Ti alloy through a nozzle in an inert gas atmosphere.