Crystallinity for epitaxial thin films of Bi-based oxide superconductor prepared at low temperature

Abstract

As-deposited thin films of superconducting Bi 2Sr 2Ca 1Cu 2O 8+δ (2212) and normally conductive Bi 2Sr 2Cu 1O 6+δ (2201) were prepared by a r.f. reactive magnetron sputtering method. Epitaxial growth of these Bi-based oxide films was realized on SrTiO 3 and MgO substrates at the relatively low temperature of 650°C. Superstructures along the a axis of the films deposited on MgO substrates were observed. Moreover, epitaxial growth of stacked 2201/2212 thin films was obtained at this temperature. Crystallinity of these thin films was evaluated by reflection high-energy electron diffraction, Rutherford backscattering spectroscopy and X-ray diffraction measurements.