Interface Properties of Single and Bi-Layer $Fe_3O_4$ Films Grown on MgO(001) Studied by RBS and Channeling Experiments

Series of $Fe_3O_4$/MgO(001) and $Fe_3O_4$/Fe/MgO(001) films (single- and bi-layer films, respectively) with a total layer thickness in the range of 20 ÷ 150 nm were investigated by the Rutherford backscattering spectrometry (2 MeV $He^{+}$ ion beam), by the Rutherford backscattering spectrometry channeling experiments (1.5 MeV $He^{+}$ ion beam). Depending on the layer thickness of each layer and the film geometry, a single Fe peak and/or a double-anomaly feature was revealed in the Rutherford backscattering spectra. For all films no magnesium presence in the surface layer was observed. For both single- and bi-layer films with a total layer thickness less than 60 nm only one minimum was observed in the channeling curves, while a double minimum was revealed for the bi-layer films with a larger thickness. X-ray reflectometry measurements have revealed that the film density is the same as that of the bulk one.