Axial orientation of molecular-beam-epitaxy-grown Fe3Si∕Ge hybrid structures and its degradation

Abstract

The axial orientation of molecular-beam-epitaxy (MBE)-grown Fe3Si(111)∕Ge(111) hybrid structures was investigated by Rutherford backscattering spectroscopy. We confirmed that during MBE above 300°C, the interdiffusion of Fe and Ge atoms results in a composition change and the epitaxial growth of FeGe in Fe3Si. Low-temperature (<200°C) MBE can realize fully ordered DO3–Fe3Si with highly axial orientation [minimum yield (χmin)=2.2%]. Postannealing above 400°C results in a composition change and the degradation of axial orientation in the off-stoichiometric Fe3Si. The significance of stoichiometry with regard to thermal stability and the interfacial quality of Fe3Si(111)∕Ge(111) hybrid structures was also discussed.