Fabrication of YBa2Cu3O7 Superconducting Film on {100}<001> Textured Cu Tape via Conductive Buffer Layers

Abstract

Long-length coated conductors (CCs) have recently become commercially available, serving as a promising candidate for use in electric power applications. However, the material and manufacturing costs are high, which discourages their use in a wide range of commercially feasible products. REBa2Cu3O7 (REBCO; RE: Y or rare-earth elements) superconducting films with high critical current density (Jc) have been grown on cube-textured metal tapes to develop CCs for high temperature, high magnetic field ap buffered Ni-W tape. CCs become highly resistive when they are quenched; therefore, for reliable and safe application, it is necessary to attach low-resistivity metal layers, such as Cu and/or Ag, to the CCs to stabilize and protect them from damage due to quenching. Presently, insulative oxides are used for the buffer layers; thus, thick Ag and Cu layers are required to be deposited as stabilizer layers on the YBCO layer. However, the high material and process costs for obtaining the Ag and Cu layers are one of the major obstacles to achieving low-cost CCs. The use of conductive buffer layers instead of insulative reduces the cost of CCs. In this paper, we propose a new configuration for CCs: YBCO deposited on a conductive Sr(Ti0.95Nb0.05)O3 buffered Ni-electroplated {100}<001> textured Cu and SUS316 lamination tape. Sr(Ti0.95Nb0.05)O3 was epitaxially grown on the Ni-electroplated {100}<001> textured Cu tape, and its resistivity was as low as 2.5 mΩ-cm at 77 K. An excellent Jc of 2.6 × 106 A/cm2 was achieved at 77 K under a magnetic self-field for the YBCO/Sr(Ti0.95Nb0.05)O3/Ni/Cu/SUS316 tape. We believe that Sr(Ti0.95Nb0.05)O3 is a promising candidate for the conductive buffer layer material.