Critical Current Density of Y–Ba–Cu Oxide Wires

We have prepared Y–Ba–Cu oxide superconducting wires with stainless-steel, Cu–Ni alloy or silver sheath by a powder metallurgy technique, and confirmed superconductivity in stainless-steel or silver-sheathed wires. During the hea-treatment, a dielectric layer was formed at the interface between the sheath and Y–Ba–Cu oxide in stainless-steel-sheathed and Cu–Ni alloy-sheathed wires. The diffusion of the sheath element into Y–Ba–Cu oxide was analyzed using EPMA. The highest critical current dernsity, 560 A/cm 2 , was obtained for a silver-sheathed wire which was heat-treated in oxygen flow. A multicored wire was produced.