There is provided a method for fabricating a device. On a top surface of a substrate, a first layer of a first deposition material is formed. The first layer of the first deposition material is patterned to create a seed pattern of remaining first deposition material. Homoepitaxy is used to grow a second layer of the first deposition material on the seed pattern.

A device, system and method for measuring the temperature at the center of a normal hotspot and the heat escape time in superconducting filament or nanowire toward the substrate. The device includes structured layers; a superconducting filament is implemented as an active layer where an electrical current pulse or single photon radiation generates a hot spot; a sensitive semiconductor layer of germanium serves as a temperature sensor (thermometer); and a thin layer of insulating silicon oxide is intercalated between the superconducting layer and the germanium having a thickness in the range of 2-10 nm and width 5-100 μm. This device provides a direct measurement of the temperature at the center of a hot spot and determination of the heat escape time toward a substrate; and can be used to determine the sensitivity of a superconducting single photon detector device to a next upcoming photon.

In various embodiments, superconducting wires feature assemblies of clad composite filaments and/or stabilized composite filaments embedded within a wire matrix. The wires may include one or more stabilizing elements for improved mechanical properties.

Superconducting integrated circuit layouts are proofed against the detrimental effects of stray flux by designing and fabricating them to have one or more ground planes patterned in the x-y plane with a regular grid of low-aspect-ratio flux-trapping voids. The ground plane(s) can be globally patterned with such voids and thousands or more superconducting circuit devices and wires can thereafter be laid out so as not to intersect or come so close to the voids that the trapped flux would induce supercurrents in them, thus preventing undesirable coupling of flux into circuit elements. Sandwiching a wire layer between patterned ground planes permits wires to be laid out even closer to the voids. Voids of successively smaller maximum dimension can be concentrically stacked in pyramidal fashion in multiple ground plane layers having different superconductor transition temperatures, increasing the x-y area available for device placement and wire-up.

A subelement (1) for an Nb.sub.3Sn-containing superconductor wire includes an Sn-containing core (2), an inner matrix (5) which includes Cu and surrounds the Sn-containing core (2), a region (7) of mutually abutting Nb-containing rod elements (8, 30), which surrounds the inner matrix (5), where the Nb-containing rod elements (8, 30) are each configured with an Nb-containing core filament (9; 31) and a Cu-containing filament casing (10), an outer matrix (6) which includes Cu and surrounds the region (7) of Nb-containing rod elements (8, 30). The Sn-containing core (2) has a core tube (3) into which an Sn-containing powder (4) has been introduced, the Sn-containing powder (4) being in a compacted state. This provides a subelement for an Nb.sub.3Sn-containing superconductor wire which cost-effectively yields an improved superconducting current carrying capacity.

Methods for electrodeposition using aqueous electrolytes where water molecules are depleted are described herein. Methods of electrodepositing superconducting thin films from aqueous electrolytes where water molecules are depleted are also described herein.

A superconducting device which includes a substrate, multiple niobium leads formed on the substrate, a niobium silicide (NbSi.sub.x) passivation layer formed on a surface of at least one of the multiple niobium leads, and an aluminum lead formed directly on at least a portion of the NbSi.sub.x passivation layer such that an interface therebetween is substantially free of oxygen and oxidized material, where the multiple niobium leads and the aluminum lead are constructed to carry a supercurrent while in use.

Superconductors and processes that form superconductors as composites of electrically polarizable ferroelectric materials and electrically conductive materials. The materials are chosen such that the binding energy of charge carriers within the materials exceeds the repulsive energy of the carriers and the energy carried by thermal vibrations (phonons) within the materials.

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

The present invention is a superconducting wire including: a wire formed of a superconducting material; and a superconducting stabilization material disposed in contact with the wire, in which the superconducting stabilization material is formed of a copper material which contains: one or more types of additive elements selected from Ca, Sr, Ba, and rare earth elements in a total of 3 ppm by mass to 400 ppm by mass; a balance being Cu and inevitable impurities, and in which a total concentration of the inevitable impurities excluding O, H, C, N, and S which are gas components is 5 ppm by mass to 100 ppm by mass.