Processing dependence of texture development in La2Zr2O7 buffer layer by sol-gel technique for YBCO coated conductors

Perovskite textured La2Zr2O7 (LZO) films were deposited on Ni tapes using sol-gel process for fabrication of second generation high-Tc superconductors. LZO solutions were derived from acetate and alkoxide precursors. The effects of precursors, solvents, chelating agents, and annealing conditions (temperature and time), on epitaxial growth of LZO were investigated by XRD, SEM, EDS, and X-ray pole figure analysis. It was found that texture of LZO depended on, solution preparation, and annealing conditions. Textured, homogenous, dense, crack free and pinhole free, LZO films were produced on textured Ni tapes by postannealing at 1150 deg. C for 10 min under 4%H2-Ar gas flow when lanthanum (III) 2-methoxyethoxide precursor and 2-methoxyethanol solvent were used. When lanthanum acetate precursor and trifluoroacetic acid were used, texture was obtained at 1160 deg. C for 40 min annealing conditions