The various embodiments described herein include methods, devices, and systems for fabricating and operating superconducting circuits. In one aspect, an electric circuit includes: (1) a first superconducting component having a first terminal, a second terminal, and a constriction region between the first terminal and the second terminal; (2) a second superconducting component having a third terminal and a fourth terminal; and (3) a first electrically-insulating component that thermally couples the first superconducting component and the second superconducting component such that heat produced at the constriction region is transferred through the first component to the second superconducting component.

Provided is a connection body of high-temperature superconducting wire materials including a first oxide high-temperature superconducting wire material and a second oxide high-temperature superconducting wire material, characterized in that a first superconducting layer of the first oxide high-temperature superconducting wire material and a second superconducting layer of the second oxide high-temperature superconducting wire material are bonded together via a junction including M-CuO (wherein M is a single metal element or a plurality of metal elements included in the first superconducting layer or the second superconducting layer). The connection body may be, for example, a connection body of Bi2223 wire materials, and the junction may include CaCuO.sub.2.

Provided is a connection body of high-temperature superconducting wire materials including a first oxide high-temperature superconducting wire material and a second oxide high-temperature superconducting wire material, characterized in that a first superconducting layer of the first oxide high-temperature superconducting wire material and a second superconducting layer of the second oxide high-temperature superconducting wire material are bonded together via a junction including M-CuO (wherein M is a single metal element or a plurality of metal elements included in the first superconducting layer or the second superconducting layer). The connection body may be, for example, a connection body of Bi2223 wire materials, and the junction may include CaCuO.sub.2.

A superconducting wire includes: a first wire including a first superconducting material layer having a first main surface; a second wire including a second superconducting material layer having a second main surface; a third wire including a third superconducting material layer having a third main surface; a first superconducting material joining layer that joins the first main surface to the second main surface; and a second superconducting material joining layer that joins the second main surface to the third main surface. The first wire has a first end surface. The third wire has a second end surface. The second end surface faces the first end surface with a space being interposed between the second end surface and the first end surface. The space is more than or equal to 10 nm and less than 1 mm.

A superconducting wire includes: a first wire including a first superconducting material layer having a first main surface; a second wire including a second superconducting material layer having a second main surface; a third wire including a third superconducting material layer having a third main surface; a first superconducting material joining layer that joins the first main surface to the second main surface; and a second superconducting material joining layer that joins the second main surface to the third main surface. The first wire has a first end surface. The third wire has a second end surface. The second end surface faces the first end surface with a space being interposed between the second end surface and the first end surface. The space is more than or equal to 10 nm and less than 1 mm.

A superconducting magnet and method for making a superconducting magnet are presented. The superconducting magnet is made by forming a coil from windings of a first wire comprising a reacted MgB.sub.2 monofilament, filling a cavity of a stainless steel billet with a Mg+B powder. Monofilament ends of the first wire and a similar second wire are sheared at an acute angle and inserted into the billet. A copper plug configured to partially fill the billet cavity is inserted into the billet cavity. A portion of the billet adjacent to the plug and the wires is sealed with a ceramic paste.

A superconducting magnet and method for making a superconducting magnet are presented. The superconducting magnet is made by forming a coil from windings of a first wire comprising a reacted MgB.sub.2 monofilament, filling a cavity of a stainless steel billet with a Mg+B powder. Monofilament ends of the first wire and a similar second wire are sheared at an acute angle and inserted into the billet. A copper plug configured to partially fill the billet cavity is inserted into the billet cavity. A portion of the billet adjacent to the plug and the wires is sealed with a ceramic paste.

A connector assembly of two low temperature superconducting cable terminals and manufacturing method thereof. A connector assembly comprises a copper layer having one side which is conducted with one low temperature superconducting cable and another side which is conducted with another low temperature superconducting cable, two welding material layers, wherein each the welding material layer is provided between the copper layer and either of the two low temperature superconducting cable, and a clip mechanism covered the outer surface of either of the low temperature superconducting cable to tightly clamp the copper layer, the two welding material layers and the two low temperature superconducting cable form the inside to the outside of the connector assembly. The connector assembly of the present invention has compact structure. The saddle-shaped copper block is compressed by a clamp mechanism is use to weld with two low temperature superconducting terminals.

A connector assembly of two low temperature superconducting cable terminals and manufacturing method thereof. A connector assembly comprises a copper layer having one side which is conducted with one low temperature superconducting cable and another side which is conducted with another low temperature superconducting cable, two welding material layers, wherein each the welding material layer is provided between the copper layer and either of the two low temperature superconducting cable, and a clip mechanism covered the outer surface of either of the low temperature superconducting cable to tightly clamp the copper layer, the two welding material layers and the two low temperature superconducting cable form the inside to the outside of the connector assembly. The connector assembly of the present invention has compact structure. The saddle-shaped copper block is compressed by a clamp mechanism is use to weld with two low temperature superconducting terminals.

A connection structure of the present disclosure includes first and second superconducting wires that are two superconducting wires each having a substrate in a tape shape, an intermediate layer formed on the substrate, and a superconductor layer formed on the intermediate layer, a connecting superconductor layer that connects the first and second superconducting wires in a positional relationship in which surfaces of the superconductor layers face each other, and forms a superconducting connecting section together with the first and second superconducting wires, two protective members each having a width larger than a width of the first and second superconducting wires and disposed on substrates sides of the first and second superconducting wires in a positional relationship of sandwiching the superconducting connecting section, and a metal part that joins the two protective members to each other.