Reconstruction of the polar interface between hexagonal LuFeO3 and intergrown Fe3O4 nanolayers

We report the observation of an unusual phase assembly behavior during the growth of hexagonal LuFeO3 thin films which resulted in the formation of epitaxial Fe3O4 nanolayers. The magnetite layers were up to 5 nm thick and grew under the conditions at which Fe2O3 is thermodynamically stable. These Fe3O4 nanolayers act as buffer layers promoting a highly epitaxial growth of the hexagonal LuFeO3 thin film up to 150 nm thick. Using scanning transmission electron microscopy, we show that the interface between ( 001) LuFeO3 and (111) Fe3O4 can be reconstructed in two ways depending on the sequence in which these compounds grow on each other. We suggest the polarity of the interface is the reason behind the observed interface reconstruction and epitaxial stabilization of magnetite.