Thermal and irradiation induced interdiffusion in magnetite thin films grown on magnesium oxide (001) substrates

Epitaxial Fe3O4(0 0 1) thin films (with a thickness in the range of 10–20 nm) grown on MgO substrates were characterized using low-energy electron diffraction (LEED), conversion electron Mossbauer spectroscopy (CEMS) and investigated using Rutherford backscattering spectrometry (RBS), channeling (RBS-C) experiments and X-ray reflectometry (XRR). The Mg out-diffusion from the MgO substrate into the film was observed for the directly-deposited Fe3O4/MgO(0 0 1) films. For the Fe3O4/Fe/MgO(0 0 1) films, the Mg diffusion was prevented by the Fe layer and the surface layer is always a pure Fe3O4 layer. Annealing and ion beam mixing induced a very large interface zone having a spinel and/or wustite formula in the Fe3O4-on-Fe film system.