Sequential electron beam evaporation of YBCO thin films through the barium fluoride route

Superconducting YBCO thin films have been fabricated by sequential electron beam evaporation of metallic constituents for yttrium and copper while barium is replaced with BaF2. The conversion of BaF2 → BaO has been attained through wet oxygen annealing. Correlations of stoichiometry with microstructural, as well as superconducting, properties of the films have been examined. Results are given for YBa2Cu3O7−δ thin films on SrTiO3 (1 0 0) and YSZ (1 0 0) single crystal substrates. The usefulness of the BaF2 preparation route for the fabrication of mixed phase (Y123 + Y124) and pure Y124 is also demonstrated. Microstructural properties of Y123 thin films indicate different growth processes for the two substrates.