Structural characterization of metastable FeSi films and of [formula omitted] multilayers

Abstract

The structural properties of molecular beam epitaxy (MBE)-grown metastable CsCl-type FeSi (i.e. an iron silicide with the CsCl lattice structure) on Si (1 1 1) and of Fe FeSi multilayers grown with MBE on MgO (0 0 1) are reported. Rutherford backscattering and channeling spectrometry (RBS-C) combined with X-ray diffraction are used to determine the structure, epitaxy and crystalline quality of the layers. Single metastable CsClFeSi layers could be stabilized epitaxially up to a thickness of 62 nm and are found to be twinned with respect to the Si (1 1 1) substrate. Moreover, an extensive study on antiferromagnetically (AF) coupled ( Fe FeSi ) 15 MgO multilayers indicates that the Fe layers are slightly expansively strained while the FeSi spacers are fully relaxed. Further, we could prove that the FeSi spacers in the multilayers have a cubic CsCl lattice structure with a lattice parameter of 0.28 nm.