Effect of Firing Temperature on the Structure and Superconducting Properties of YBa2Cu3O7−x Films

YBa2Cu3O7−x (YBCO) films were prepared on LaAlO3 single crystal substrate under various firing temperatures (750–800 °C) in the crystallization process by metalorganic deposition (MOD) method. The coating solution was made by mixing the fluorine-free precursor solution containing Y and Cu with Ba–fluorine precursor solution (Ba-TFA). The effect of firing temperature on the structure and superconducting properties of YBCO films was systematically investigated. The results indicated that YBCO-films were smooth, crack-free, exhibited good textures and retain high oxygen content according to the XRD and SEM images. Sample of YBCO-film fired at 780 °C showed highest superconducting properties including high critical transition temperature T c=89 K, sharp transition temperature ΔT c<1 K, and critical current density J c=2.8 MA cm−2, which are attributable to excellent in-plane textures and dense microstructures with good connectivity between the grains.