Growth of epitaxial Y₂O₃ buffer layers on biaxially textured Ni-W substrates for YBCO coated conductors by MOD approach

We have grown epitaxial Y₂O₃ buffer layers on biaxially textured Ni-W substrates for YBCO coated conductors using a newly developed metal organic decomposition (MOD) approach. Y₂O ₃ precursor solution of 0.25 M concentration was spin coated on short samples of Ni-3 at.%W (Ni-W) substrates and heat-treated at 1150 °C in a gas mixture of Ar-4% H₂ for an hour. Detailed X-ray studies indicate that Y₂O₃ films have good out-of-plane and in-plane textures with full-width-half-maximum values of 6.22° and 7.51°, respectively. SEM and AFM investigations of Y₂O ₃ films reveal a fairly dense and smooth microstructure without cracks and porosity. Highly textured YSZ barrier layers and CeO₂ cap layers were deposited on MOD Y₂O₃-buffered Ni-W substrates using rf-magnetron sputtering. Pulsed laser deposition was used to grow YBCO films on these substrates. A critical current, J_c, of about 1.21 MA/cm² at 77 K and self-field was obtained on YBCO (PLD)/CeO₂ (sputtered)/YSZ (sputtered)/Y₂O₃ (spin-coated)/Ni-W.