Preparation of buffer layer architectures for YBa_2Cu_3O_(7-x) coated conductors based on surface oxidized Ni tapes

摘要

Cube textured NiO layers were prepared by surface oxidation epitaxy on microalloyed Ni tapes. Different perovskite buffers were successfully grown on these substrates using pulsed laser deposition. Among them, BaZrO_3 and SrZrO_3 buffers show an excellent epitaxial growth on NiO with an in-plane orientation similar to the underlying NiO. The subsequent deposition of YBa_2Cu_3O_(7-x) on top of these buffers requires a thin intermediate SrTiO_3 layer and results in epitaxial layers with a T_c of about 89 K and J_c values up to 1.6 MA cm~(-2). Alternatively, epitaxial SrRuO_3 was grown on NiO using a thin intermediate BaZrO_3 layer leading to YBCO films of similar quality. The investigation of the magnetic field dependence of the critical current density shows the major influence of the grain boundary network in the low-field region.