Iron oxide on (001) MgO

Transmission and scanning electron microscopy have been used to characterize thin films of Fe oxide grown on (001)-oriented MgO using pulsed-laser deposition. Several films, each with a longer deposition time, and hence increasing thickness, were grown under similar conditions of oxygen pressure, deposition rate and substrate temperature. For shorter deposition times, i.e. thinner films, a spinel-structured Fe oxide film occurred, while for longer deposition times a corundum-structured Fe oxide film formed. In some instances it was found that the film had a mixture of the two structures of Fe oxide. The analysis of these films determined that the corundum-structured Fe oxide was being formed via a transformation from the spinel structure. This transformation process led to interesting thin-film morphologies and epitactic alignments.