High critical current density YBa₂Cu₃O₇ coating on conductive Nb-doped SrTiO₃ and Ni double-buffered {100}〈001〉 textured pure Cu tape for low-cost coated conductors without generation of any insulative oxides at interfaces

Abstract

For development of a low-cost superconducting wire operating at high temperature, we propose a new approach using conductive rather than insulating buffer layers, combined with {100}<001> textured pure Cu tape to form YBa 2 Cu 3 O 7 /Nb-doped SrTiO 3 /Ni/Cu/stainless steel. The critical current density of the YBa 2 Cu 3 O 7 layer was 2.5 MA/cm 2 at 77 K in a magnetic self-field. We also confirmed that some current flowed into the Cu tape through the conductive buffer layers when the current exceeded the critical current of the YBa 2 Cu 3 O 7 layer, suggesting that the textured Cu tape worked not only as a biaxial template but also as a stabilizer layer.