Structural and transport properties of YBa2Cu3O7−δ thin films subjected to different heat treatments and, consequently, having different O vacancy contents were investigated. It was observed that lattice parameters of the films follow the trend of the bulk material, indicating that either the additional stresses created in c-axis oriented films by O vacancies were negligibly small or they were relaxed at elevated temperatures. In addition, heat treatment under relatively low O2 partial pressures, used to create O vacancies, led to considerable reduction in local variations of lattice spacings in YBa2Cu3O7−δ thin films.

Microstructural Changes in Epitaxial YBa2Cu3O7−δ Thin Films Due to Creation of O Vacancies. Y.Kuru, M.Usman, G.Cristiani, H.U.Habermeier: Journal of Crystal Growth, 2010, 312[20], 2904-8