Crystallization of YBa2Cu3O7-y films on SrTiO3(100) by postannealing of precursors prepared by dipping-pyrolysis process

Abstract

The effects of annealing temperature and oxygen partial pressure [p(O2)] were investigated on the crystallization and orientation of superconducting YBa2Cu3O7-y (YBCO) films on SrTiO3(100) prepared by the dipping-pyrolysis process. Annealing conditions for precursor films consisting of a Y2O3—BaCO3—CuO mixture were varied in the temperature range 700–850 °C and initial p(O2) range 2 × 10-4-10-2 atm followed by pure O2 treatment. Three different types of crystallization behavior were observed. The c-axis-oriented epitaxial YBCO films were obtained on the lower p(O2) and higher temperature side in the p(O2)-T diagram. The c/a-axis-oriented growth was observed in films heat-treated at 750–800 °C under p(O2) of 10-3 atm. In addition, mixtures of YBCO and YBa2Cu4O8 resulted when the films were annealed at 700 °C.