Improved interfacial local structural ordering of epitaxial Fe3Si(001) thin films on GaAs(001) by a MgO(001) tunneling barrier

摘要

Although the quasi-Heusler compound Fe3Si is a promising candidate for spintronics applications, its combination with the reactive GaAs surface is problematic, since it deteriorates its beneficial attributes due to a large amount of interdiffusion at the Fe3Si/GaAs interface. Here, we show the epitaxial growth of Fe3Si with low evaporation rates on GaAs(OOl) and report on improved local structural D03 ordering in epitaxial Fe3Si(001) films grown on GaAs(OOl) by inserting a MgO buffer layer. Conversion-electron Mossbauer spectroscopy with 57Fe3Si tracer layers reveals that the effect of thermally induced interdiffusion at the Fe3Si/GaAs(001) interface is dramatically reduced by inserting a 30 A MgO tunneling barrier between the film and the substrate. The chemical order of Fe3Si is comparable to that of Fe3Si films which are grown directly on MgO(OOl) single crystals. It is proposed that this preparation method can be useful to achieve high-efficiency spin-polarized electron currents from ferromagnetic Fe3Si into semiconducting GaAs(OOl).