(La, Sr)TiO₃ as a conductive buffer for high-temperature superconducting coated conductors

The perovskite (La, Sr)TiO₃ was investigated as a possible conducting oxide buffer layer for high-temperature superconducting coated conductors. In particular, the growth of LSTO films on SrTiO₃ single crystal, Ni-W, and Cu tapes was performed using pulsed laser deposition. LSTO films were grown in vacuum at a temperature of 750°C. From the ω-scan, the FWHM values of LSTO (004) on Ni-W and Cu tape were 7.48° and 6.21°, which showed improvement in the out-of-plane texture for the film as compared to the substrate metal tapes. The phi;-scans through the LSTO (112) on both metal tapes indicated in-plane-aligned LSTO grains. YBa₂Cu ₃O₇ films were deposited on all three structures by pulsed laser ablation; samples on LSTO/SrTiO₃ single crystals had a superconducting transition of 91°K and a Jc value of 3.0 M A/cm². This shows that LSTO is a good template for the YBCO film in terms of epitaxial and chemically stable growth.