Y-Ba-Cu-O film growth on Y2O3 buffered and nonbuffered SrTiO3 single crystals using precursor films including fluoride

A fluoride compound, BaF₂, was used in the ex situ post-reaction process which was effective in the preparation of thick YBa₂Cu₃O_7-x (YBCO) films over 1 micrometers for coated conductors. We investigated the YBCO film growth on SrTiO₃ single crystal with and without Y₂O₃ buffer layers using BaF₂. In order to suppress the reaction between the YBCO precursor films and the Y₂O₃ buffer layer, we controlled the atmospheric pressure and changed the evaporation materials to obtain precursor films which included fluoride. No water vapor was introduced during the heat treatment. The epitaxy c-axis oriented YBCO films, with 0.3 μm thickness, were successfully grown on both the Y₂O₃ buffered and nonbuffered SrTiO₃ single crystals using Y, BaF₂ and Cu as evaporation sources. We also deposited YBCO films on both substrates using evaporation sources, YF₃, Ba and Cu. An appreciably different result has been obtained using YF₃ compared to that using BaF₂