Optimisation of deposition and annealing parameters for preparation of high quality YBa2Cu3Osub(7-x) thin films by spray pyrolysis technique

Superconducting films of YBa2Cu3Osub(7-x)(YBCO) had been prepared on single crystal MgO(100) substrate using simple and low cost spray pyrolysis technique. Process parameters for preparation of good quality superconducting films were investigated and optimized. Various annealing procedures had been used to make films with high critical temperature (Tc) and critical current density (Jc). The films were characterized by Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Energy Dispersive X-ray Spectroscopy (EDS) and measurements of resistance vs temperature characteristics, Jc and thickness. The morphology and orientation of these films had been successfully controlled by employing suitable annealing processes. The films were highly oriented with c-axis usually perpendicular to the substrate. The highest Tc(R =0) attained for such films is 89K. The Jc of the films is of the order of 104 A/cm2 at 77K in zero magnetic field. The films are granular in nature with Josephson weaklinks formed across the grain boundaries. (author). 31 refs., 17 figs., 5 tabs