Thick YBa₂Cu₃O₇ films by post annealing of the precursor by high rate e-beam deposition on SrTiO₃ substrates

High rate evaporation techniques were used to deposit Y, BaF₂, and Cu precursor films onto SrTiO₃ single crystal substrates at rates in excess of 10 nm/s. Y and Cu were deposited by electron beam (e-beam) heating and thermal heating was used for BaF₂. Post deposition annealing was used to form 3 μm thick c-axis aligned YBa₂Cu₃O₇ films on the SrTiO₃ substrates. Critical current densities 1.8 × 10⁵ A/cm² at 1 T (H∥c) and 77 K were achieved. The films were nominally stoichiometric and were post-deposition annealed in a humidified reduced oxygen atmosphere at 725-800°C. These results indicate that the so-called BaF₂ post annealing process can be one of several possible candidate methods for production of thick YBa₂Cu₃O₇ coatings for large scale applications.