Surface Analysis of C-Axis-Oriented YBa2Cu3O7-X Thin Films by QMS, XPS and LEED: Effects of In-Vacuum Annealing

Abstract
The effects of in-vacuum annealing on the crystallinity and superconductivity in the surface region of YBa2Cu3O7-X thin films were investigated by QMS, XPS and LEED. Contaminated and disordered layers, which were nonsuperconducting phase, covered the film surface after being exposed to air. Surface contaminants are removed by annealing at 350°C in ultra high vacuum. The orthorhombic YBa2Cu3O7-X (001) structure and superconducting phase are obtained at the outermost surface after annealing at 350-400°C.