Structure and interface chemistry of perovskite-spinel nanocomposite thin films

The structure and the interface chemistry of epitaxial BiFeO3–NiFe2O4 nanocomposite thin films on SrTiO3(001) substrates were investigated using the Z-contrast imaging and the electron exit-wave reconstruction methods at the atomic scale. The results show that the NiFe2O4 pillars are nonwetting with respect to the substrate and exhibit {111} facets at the surface. The interface between BiFeO3 and NiFe2O4 lies in the {110} planes and is semicoherent. The atomic configuration of the interface, with the BiFeO layer bonding to the [Ni,Fe]O2 layer, was shown to have the maximized structure continuity and minimized interface charging.