An architecture for, and techniques for fabricating, a thermal decoupling device are provided. In some embodiments, thermal decoupling device can be included in a thermally decoupled cryogenic microwave filter. In some embodiments, the thermal decoupling device can comprise a dielectric material and a conductive line. The dielectric material can comprise a first channel that is separated from a second channel by a wall of the dielectric material. The conductive line can comprise a first segment and a second segment that are separated by the wall. The wall can facilitate propagation of a microwave signal between the first segment and the second segment and can reduce heat flow between the first segment and the second segment of the conductive line.

An architecture for, and techniques for fabricating, a thermal decoupling device are provided. In some embodiments, thermal decoupling device can be included in a thermally decoupled cryogenic microwave filter. In some embodiments, the thermal decoupling device can comprise a dielectric material and a conductive line. The dielectric material can comprise a first channel that is separated from a second channel by a wall of the dielectric material. The conductive line can comprise a first segment and a second segment that are separated by the wall. The wall can facilitate propagation of a microwave signal between the first segment and the second segment and can reduce heat flow between the first segment and the second segment of the conductive line.

A superconducting coil includes: a winding member 12 that has a side surface 18 along a coil radial direction and is formed by laminating a superconducting tape wire 20 in the coil radial direction by winding; and a bypass 19 that is provided on the side surface 18 of the winding member 12 and electrically connects the superconducting tape wire 20 in the coil radial direction.

A superconducting coil includes: a winding member 12 that has a side surface 18 along a coil radial direction and is formed by laminating a superconducting tape wire 20 in the coil radial direction by winding; and a bypass 19 that is provided on the side surface 18 of the winding member 12 and electrically connects the superconducting tape wire 20 in the coil radial direction.

Described are cable joints and related structures and techniques for coupling high temperature superconducting (HTS) cables. A cable joint includes a conductive member having a length which defines the length of the joint and having first and second mounting regions shaped to accept first and second HTS cable with an interface layer comprised of a malleable metal disposed between a surfaces of the first and second mounting regions and surfaces of the first and second HTS cables.

Described are cable joints and related structures and techniques for coupling high temperature superconducting (HTS) cables. A cable joint includes a conductive member having a length which defines the length of the joint and having first and second mounting regions shaped to accept first and second HTS cable with an interface layer comprised of a malleable metal disposed between a surfaces of the first and second mounting regions and surfaces of the first and second HTS cables.

When temperature raising is performed, temperature of a superconducting cable is uniformly raised over an entirety of the superconducting cable. The superconducting cable assumes a linear shape when cooled, and deforms into a helical shape when temperature raising is performed. In a former having a twisted wire structure, twisting directions of an outermost layer and a layer next to the outer most layer are set to be the same, enabling stabilization of the helical deformation of the superconducting cable including the former when the temperature raising is performed.

When temperature raising is performed, temperature of a superconducting cable is uniformly raised over an entirety of the superconducting cable. The superconducting cable assumes a linear shape when cooled, and deforms into a helical shape when temperature raising is performed. In a former having a twisted wire structure, twisting directions of an outermost layer and a layer next to the outer most layer are set to be the same, enabling stabilization of the helical deformation of the superconducting cable including the former when the temperature raising is performed.

The following two problems arise when carbon is added to a starting material powder in the process of production of an MgB.sub.2 superconductor: (1) an impurity phase increases; and (2) the degree of substitution of carbon at boron sites is spatially non-uniform. This superconductor production method comprises: a mixing step of mixing a starting material powder and an additive; and a heat treatment step of heat-treating the mixture prepared in the mixing step. The starting material powder is MgB.sub.2 powder or a mixed powder of magnesium and boron, and the additive is an Mg—B—C compound containing three elements of magnesium, boron and carbon.

The following two problems arise when carbon is added to a starting material powder in the process of production of an MgB.sub.2 superconductor: (1) an impurity phase increases; and (2) the degree of substitution of carbon at boron sites is spatially non-uniform. This superconductor production method comprises: a mixing step of mixing a starting material powder and an additive; and a heat treatment step of heat-treating the mixture prepared in the mixing step. The starting material powder is MgB.sub.2 powder or a mixed powder of magnesium and boron, and the additive is an Mg—B—C compound containing three elements of magnesium, boron and carbon.