Structural and electronic response via oxygen vacancy control in SrFeO3 heterostructures

The electronic and structural properties of complex perovskite oxide thin films are often directly influenced by their oxygen vacancy concentration. Here, we investigate epitaxial films of SrFeO$_{\mathrm{3}}$, which exhibits a variety of structural and electronic phases as a function of oxygen content. The ability to control these functional properties via temperature or external fields is not present in conventional semiconductors and is attractive from an application perspective. As-grown films are oxidized using a post-growth anneal in dilute ozone, yielding metallic behavior consistent with bulk SrFeO$_{\mathrm{3}}$. X-ray diffraction and temperature dependent resistivity collected at different stages of oxidation and reduction reveal minute structural transformations that yield large changes in electronic behavior due to oxygen loss.