Composition of MBE-grown iron oxide films

A wide range of iron oxides have been grown epitaxially on MgO(100) substrates using a dual beam technique in which the deposited iron is oxidised by a beam of NO2 particles. At high fluxes magnetite (Fe3-deltaO4) phases with compositions between near-stoichiometric magnetite (Fe3O4, delta = 0) and maghemite (gamma-Fe2O3, delta = 1/3) are obtained and at low fluxes wustite (Fe1-xO1-yNy) phases. The nature and composition of these phases was determined by combining the results of Mossbauer spectroscopy, RHEED, XPS and ion scattering techniques