MOD approach for the growth of epitaxial CeO₂ buffer layers on biaxially textured Ni-W substrates for YBCO coated conductors

We have grown epitaxial CeO₂ buffer layers on biaxially textured Ni-W substrates for YBCO coated conductors using a newly developed metal organic decomposition (MOD) approach. 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 1100°C in a gas mixture of Ar-4%H₂ for 15 min. Detailed x-ray studies indicate that CeO₂ films have good out-of-plane and in-plane textures with full-width-half-maximum values of 5.8° and 7.5°, respectively. High temperature in situ XRD studies show that the nucleation of CeO₂ films starts at 600°C and the growth completes within 5 min when heated at 1100°C. SEM and AFM investigations of CeO₂ films reveal a fairly dense microstructure without cracks and porosity. Highly textured YSZ barrier layers and CeO₂ cap layers were deposited on MOD CeO₂-buffered Ni-W substrates using rf-magnetron sputtering. Pulsed laser deposition (PLD) was used to grow YBCO films on these substrates. A critical current, J_c, of about 1.5 MA cm^-2 at 77 K and self-field was obtained on YBCO (PLD)/CeO₂ (sputtered)/YSZ (sputtered)/CeO₂ (spin-coated)/Ni-W.