The purpose of the present invention is to provide a niobium-aluminum precursor wire having properties such as expression of flexibility and ensuring a large single-wire length, as well as a twisted wire, a superconducting wire, and a superconducting twisted wire formed of the niobium-aluminum precursor wire. The present invention provides a niobium-aluminum precursor wire and a twisted wire using the same, the niobium-aluminum precursor wire including: a rod-like winding core (5) formed of a stabilized copper, or a stabilized copper and an unstabilized copper; a laminated body (3) that is wound around the winding core (5) and that is formed of an aluminum foil and a niobium foil laminated one on the other; and a covering body (1) that covers the circumference of the laminated body and that is formed of a stabilized copper, or a stabilized copper and an unstabilized copper. The volume ratio of the stabilized copper with respect to the unstabilized copper contained in the precursor wire is 0.5-2.0, and the volume ratios of the stabilized copper contained in the winding core (5) and the covering body (1) are within prescribed ranges. According to the present invention, a superconducting wire and a superconducting twisted wire are provided by thermally treating the precursor wire and the twisted wire.

A method, system, and apparatus for fabricating a high-strength Superconducting cable comprises pre-oxidizing at least one high-strength alloy wire, coating at least one Superconducting wire with a protective layer, and winding the high-strength alloy wire and the Superconducting wire to form a high-strength Superconducting cable.

A bundle of superconducting cables employs a plurality of superconducting cables, each having a former and a plurality of superconducting tape conductors wound in at least one layer around the former in a helical fashion. Each superconducting tape conductor has at least one superconducting layer. Each superconducting cable lacks an outer insulating layer and is held in a bundle of cables with each other superconducting cable of the plurality of superconducting cables. A sheath of non-conductive material covers the bundle of cables.

A bundle of superconducting cables employs a plurality of superconducting cables, each having a former and a plurality of superconducting tape conductors wound in at least one layer around the former in a helical fashion. Each superconducting tape conductor has at least one superconducting layer. Each superconducting cable lacks an outer insulating layer and is held in a bundle of cables with each other superconducting cable of the plurality of superconducting cables. A sheath of non-conductive material covers the bundle of cables.

The flexible superconducting micro-coaxial cable is designed for use in quantum computing systems. The micro-coaxial cable includes an inner conductor made of a first superconductive material, surrounded by a dielectric layer. Circumferentially surrounding the dielectric layer is a braided outer conductor, made of a second superconductive material, providing more than 90% coverage. The first and second superconductive materials can be either type-I superconductors, such as Aluminum (Al), Lead (Pb), Titanium (Ti), Indium (In), and Tin (Sn), or type-II superconductors, including magnesium diboride (MgB2), niobium-titanium (NbTi), niobium-tin (Nb3Sn), and niobium-germanium (Nb3Ge).

The flexible superconducting micro-coaxial cable is designed for use in quantum computing systems. The micro-coaxial cable includes an inner conductor made of a first superconductive material, surrounded by a dielectric layer. Circumferentially surrounding the dielectric layer is a braided outer conductor, made of a second superconductive material, providing more than 90% coverage. The first and second superconductive materials can be either type-I superconductors, such as Aluminum (Al), Lead (Pb), Titanium (Ti), Indium (In), and Tin (Sn), or type-II superconductors, including magnesium diboride (MgB2), niobium-titanium (NbTi), niobium-tin (Nb3Sn), and niobium-germanium (Nb3Ge).

A compound superconducting wire 10 includes a reinforcement portion 12 and a compound superconductor 11. In the reinforcement portion 12, an assembly of plural reinforcement elements 4 are disposed. The reinforcement elements 4 each include plural reinforcement filaments 1 disposed in a stabilizer 2, and a stabilizing layer 3 at the outer periphery thereof. The reinforcement filaments 1 each mainly contain one or more metals selected from the group consisting of Nb, Ta, V, W, Mo, Fe, and Hf, an alloy consisting of two or more metals selected from the aforementioned group, or an alloy consisting of copper and one or more metals selected from the aforementioned group.

A compound superconducting wire 10 includes a reinforcement portion 12 and a compound superconductor 11. In the reinforcement portion 12, an assembly of plural reinforcement elements 4 are disposed. The reinforcement elements 4 each include plural reinforcement filaments 1 disposed in a stabilizer 2, and a stabilizing layer 3 at the outer periphery thereof. The reinforcement filaments 1 each mainly contain one or more metals selected from the group consisting of Nb, Ta, V, W, Mo, Fe, and Hf, an alloy consisting of two or more metals selected from the aforementioned group, or an alloy consisting of copper and one or more metals selected from the aforementioned group.

A compound superconducting twisted wire includes compound superconducting strands being twisted to form a twisted structure, in which each of the compound superconducting strands includes a compound superconductor part, a reinforcing part and a stabilizing part. The compound superconductor part includes compound superconducting filaments and a first matrix, the compound superconducting filaments each including a compound superconducting phase. The reinforcing part is disposed on an outer circumferential side of the compound superconductor part and includes reinforcing filaments and a second matrix. The stabilizing part is disposed on at least one side of an inner circumferential side and an outer circumferential side of the reinforcing part. A volume ratio of the reinforcing part relative to the compound superconducting strand is larger than a volume ratio of the compound superconductor part relative to the compound superconducting strand.

A compound superconducting twisted wire includes compound superconducting strands being twisted to form a twisted structure, in which each of the compound superconducting strands includes a compound superconductor part, a reinforcing part and a stabilizing part. The compound superconductor part includes compound superconducting filaments and a first matrix, the compound superconducting filaments each including a compound superconducting phase. The reinforcing part is disposed on an outer circumferential side of the compound superconductor part and includes reinforcing filaments and a second matrix. The stabilizing part is disposed on at least one side of an inner circumferential side and an outer circumferential side of the reinforcing part. A volume ratio of the reinforcing part relative to the compound superconducting strand is larger than a volume ratio of the compound superconductor part relative to the compound superconducting strand.