A method and apparatus for quality control of superconducting tapes, comprising non-destructive and non-contact methods for measuring the surface resistance of a superconducting tape during tape growth. The dielectric resonator techniques of the present invention can be adapted for measurements at the elevated temperatures used during annealing as well as at room and lower temperatures, providing the opportunity for real-time quality control of semiconductor tapes as they are being fabricated.

A superconducting composition of matter including overlapping first and second regions. The regions comprise unit cells of a solid, the first region comprises an electrical insulator or semiconductor, and the second region comprises a metallic electrical conductor. The second region extends through the solid and a subset of said second region comprise surface metal unit cells that are adjacent to at least one unit cell from the first region. The ratio of the number of said surface metal unit cells to the total number of unit cells in the second region being at least 20 percent.

Provided is a superconducting wire. The superconducting wire comprises a substrate, a superconducting film on the substrate and a pinning center in the superconducting film. The superconducting film includes Y.sub.1-xRE.sub.xBCO and the pinning center has an additive of Ba.sub.2YNbO.sub.6.

A superconducting composition of matter including overlapping first and second regions. The regions comprise unit cells of a solid, the first region comprises an electrical insulator or semiconductor, and the second region comprises a metallic electrical conductor. The second region extends through the solid and a subset of said second region comprise surface metal unit cells that are adjacent to at least one unit cell from the first region. The ratio of the number of said surface metal unit cells to the total number of unit cells in the second region being at least 20 percent.