Production of YBa₂Cu₃O_7−x superconducting thin films by pulsed pseudospark electron beam evaporation

Abstract

Thin-film superconducting YBa₂Cu₃O_7−x layers have been produced in a single-step process by pulsed electron beam evaporation from a stoichiometric 1-2-3 target. The films were produced at the 〈100〉 surface of SrTiO₃ substrates heated to a temperature of approximately 1000 K in a pure oxygen atmosphere of about 10 Pa total pressure. After deposition the films were cooled in situ within 20 minutes to ambient temperature. At present, the films are polycrystalline and show a T_c,zero of 83 K with a transition width of 3–5 K. Critical current densities of 7·10⁴ A/cm² at 4.2 K and zero magnetic field have been achieved. The pulsed electron beams used in these experiments are produced by a pseudospark discharge; the estimated energy density deposited at the target surface by the electron beam is of the order of 4 J/cm².