Study of Ta-doped CeO2 Buffer Layer for Coated Conductors

Ta-doped CeO2 buffer layers were grown on the home-made textured Ni-5W substrates for YBCO coated conductors by a simple metal-organic deposition technique. The characterization of the samples was discussed. XPS results indicate that Ta5+ is reduced into Ta4+ prior to Ce4+, which is helpful to suppress the formation of holes and cracks in CeO2 films from reducing Ce4+ into Ce3+. Additionally, no new phase is found by doping Ta into CeO2, which indicates that Ta4+ replaces the Ce4+ position in CeO2 lattice to form Ce0.75Ta0.25O2. The Ce0.75Ta0.25O2 has a good out-of-plane and in-plane texture FWHM values for ω scan and ϕ scan are 4.38° and 6.67°, respectively. AES measurements show that no Ni element is detected on the surface of Ce0.75Ta0.25O2 film, and a one-layer film has a thickness of about 70 nm. It is promising that the presently developed Ce0.75Ta0.25O2 film can be used as a single multi-functional buffer layer for coated conductor.