A tunable oscillator including a Josephson junction. In some embodiments, the tunable oscillator includes a first superconducting terminal, a second superconducting terminal, a graphene channel including a portion of a graphene sheet, and a conductive gate. The first superconducting terminal, the second superconducting terminal, and the graphene channel together may form a Josephson junction having an oscillation frequency, and the conductive gate may be configured, upon application of a voltage across the conductive gate and the graphene channel, to modify the oscillation frequency.

A fiber optical superconducting nanowire detector with increased detector efficiency, fabricated directly on the tip of the input optical fiber. The fabrication on the tip of the fiber allows precise alignment of the detector to the fiber core, where the field mode is maximal. This construction maximizes the coupling efficiency to close to unity, without the need for complex alignment procedures, such as the need to align the input fiber with a previously fabricated device. The device includes a high-Q optical cavity, such that any photon entering the device will be reflected to and fro within the cavity numerous times, thereby increasing its chances of absorption by the nanowire structure. This is achieved by using dedicated cavity mirrors with very high reflectivity, with the meander nanowire structure contained within the cavity between the end mirrors, such that photons impinge on the nanowire structure with every traverse of the cavity.

This disclosure will describe a novel finding and make the claim for the first time on a group of old compounds and formulated new compounds. These compounds have superconducting property at high temperatures, i.e., 151K or higher. Several compounds were prepared, though not well-purified, at around middle of 1900s. Their chemical, structural, electric and magnetic properties were studied and reported but their superconducting property has not been known and has never been exploited because the idea of type-II superconductivity was not proposed at that time. Consequently, we claim this finding as an invention even though our invention is based on the studies of the compounds' electric and magnetic properties along with their crystallographic features from the previous publications. The experiments to further verify their high temperature superconductivity require the utilization of sophisticated facilities on synthesizing highly pure compounds and the deregulation from government security authorities on purchasing the starting 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 relates to a precursor (1) for production of a high-temperature superconductor (HTS) in ribbon form, comprising a metallic substrate (10) in ribbon form having a first ribbon side (11) and a second ribbon side (12), wherein, on the first ribbon side (11), (a) the substrate (10) has a defined texture as template for crystallographically aligned growth of a buffer layer or an HTS layer and (b) an exposed surface of the substrate (10) is present or one or more layers (20,30) are present that are selected from the group consisting of: buffer precursor layer, pyrolyzed buffer precursor layer, buffer layer, HTS precursor layer, pyrolyzed HTS buffer precursor layer and pyrolyzed and further consolidated HTS buffer precursor layer, and, on the second ribbon side (12), at least one ceramic barrier layer (40) that protects the substrate (10) against oxidation or a precursor which is converted to such a layer during the HTS crystallization annealing or the pyrolysis is present, wherein, when one or more layers (20, 30) are present on the first ribbon side (11), the ceramic barrier layer (40) or the precursor thereof has a different chemical composition and/or a different texture than the layer (20) arranged on the first ribbon side (11) and directly adjoining the substrate (10). In this precursor, the barrier layer (40) is a layer that delays or prevents ingress of oxygen to the second ribbon side (12) and is composed of conductive ceramic material or a precursor which is converted to such a precursor during the HTS crystallization annealing or the pyrolysis, and the ceramic material is an electrically conductive metal oxide or an electrically conductive mixture of metal oxides, wherein the conductive metal oxide or one or more metal oxides in the conductive mixture is/are preferably metal oxide(s) doped with an extraneous metal.

A superconducting oxide thin film includes a superconducting layer formed on a supporting material. The superconducting layer includes an RE-based superconductor as a main component, and the RE-based superconductor includes a CuO chain that has a Cu vacancy portion.

Various techniques and apparatus permit fabrication of superconductive circuits. A niobium/aluminum oxide/niobium trilayer may be formed and individual Josephson Junctions (JJs) formed. A protective cap may protect a JJ during fabrication. A hybrid dielectric may be formed. A superconductive integrated circuit may be formed using a subtractive patterning and/or additive patterning. A superconducting metal layer may be deposited by electroplating and/or polished by chemical-mechanical planarization. The thickness of an inner layer dielectric may be controlled by a deposition process. A substrate may include a base of silicon and top layer including aluminum oxide. Depositing of superconducting metal layer may be stopped or paused to allow cooling before completion. Multiple layers may be aligned by patterning an alignment marker in a superconducting metal layer.

Disclosed is a method to modify the superconductive properties of a potentially or effectively superconductive material. The method includes providing a reflective or photonic structure and placing said superconductive material in or on the structure. The method also includes providing a structure which has an electromagnetic mode which is resonant with a transition in the material and controlling, in particular enhancing, the superconductivity, and thus the mobility of the charge carriers. This results in a higher operating temperature and an increased electrical current in the material, by means of strongly coupling the material to the local electromagnetic vacuum field and exploiting the formation of states of spatial extension corresponding to the mode volume of the electromagnetic resonance. Also disclosed is an electronic, electro-optical or optoelectronic device including superconductive material located in or on a reflective or photonic structure.

A superconductive cable including: a former; one or more superconductive conductor layers provided outside the former; an insulating layer configured to surround the superconductive conductor layers; and one or more superconductive shield layers provided on an exterior of the insulating layer. The superconductive conductor layers and the superconductive shield layers are formed of superconductive wire rods, and each superconductive wire rod includes a metal substrate layer and a plurality of superconducting layers deposited on the metal substrate layer using a superconductive material. In the superconductive wire rods of an outermost superconductive conductor layer among the superconductive conductor layers and an innermost superconductive shield layer among the superconductive shield layers, each of the metal substrate layers and the superconducting layers are disposed in opposite directions.

A method and composition for doped HTS tapes having directional flux pinning and critical current.