Fabrication of RE123 layer for coated conductor by double LPE process

Abstract

RE123 superconductive oxides are expected to be utilized for electric conductors due to its superconducting performance better than Bi-system superconductors at 77 K. The liquid phase epitaxy (LPE) process has the advantage of fabricating a thick superconducting layer at a high growth rate maintaining high Jc values in comparison with commonly used vapor deposition processes. We tried to fabricate the double layered LPE process for realizing an in-plane aligned RE123 layer on a textured Ni substrate with a NiO buffer layer. The in-plane aligned double layered LPE structure was successfully grown on NiO/Ni textured substrates and showed a Tc value of 88 K. The in-plane alignment of the seed layer was found to be a crucial factor for the double LPE process because the partial dissolution of badly aligned seed crystals caused formation of non-coverage regions on the surface of the NiO buffer layer, where the NiO buffer layer would react with the solution during the second LPE processing. The in-plane aligned Sm123-Ni LPE layer was successfully grown on 10 cm long NiO/Ni textured substrates using the LPE apparatus by moving a metal tape laterally on the surface of the solution. A growth rate higher than 1 μm/min was attained. Additionally, a non-reactive buffered structure using BaZrO3 suitable for the LPE process was proposed.