(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 degrees C. From the omega-scan, the FWHM values of LSTO (004) on Ni-W and Cu tape were 7.48 degrees and 6.21 degrees, 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. YBa2Cu3O7 films were deposited on all three structures by pulsed laser ablation; samples on LSTO/SrTiO3 single crystals had a superconducting transition of 91 degrees K and a Jc value of 3.0 MA/cm(2). This shows that LSTO is a good template for the YBCO film in terms of epitaxial and chemically stable growth.