UC Berkeley

The epitaxial (001)-oriented 250 nm BiFeO3 /50 nm SrRuO 3 films were deposited on DyScO3 and SrTiO3 substrates, respectively. Following the growth, the cooling in lower oxygen pressure results in the creation of oxygen vacancies at the surface of the BiFeO3 film and the epitaxial strain drives these vacancies to diffuse from the film surface to the film interface. The SrTiO3 substrate strongly absorbs oxygen vacancies from the BiFeO3 film while the DyScO3 substrate does not. Therefore, the depth distribution of oxygen vacancies depends on the oxygen pressure during cooling, the epitaxial strain, and the substrate absorbing oxygen vacancies. © 2009 American Institute of Physics.