We investigated the magnetic as well as the structural properties of ${\text{Fe}}_3\text{Si}$ films on $\text{GaAs}\left(001\right)\text{−}\left(4\times 6\right)$, $\text{GaAs}\left(001\right)\text{−}\left(2\times 2\right)$, and MgO(001) by x-ray magnetic circular dichroism (XMCD) and Mössbauer spectroscopy. From the XMCD spectra we determine averaged magnetic moments of $1.3–1.6{\mu }_{\text{B}}$ per Fe atom on the different substrates by a standard sum-rule analysis. In addition, XMCD spectra have been calculated by using the multiple-scattering Korringa-Kohn-Rostoker method which allows the site-specific discussion of the x-ray spectra. The Mössbauer spectra show a highly ordered and stoichiometric growth of ${\text{Fe}}_3\text{Si}$ on MgO while the growth on both GaAs substrates is strongly perturbed, probably due to diffusion of substrate atoms into the ${\text{Fe}}_3\text{Si}$ film. Therefore, we have studied the influence of Ga or As impurities on the magnetic properties of ${\text{Fe}}_3\text{Si}$ by calculations using coherent-potential approximation within the Korringa-Kohn-Rostoker method. For selected impurity concentrations additional supercell calculations have been performed using a pseudopotential code (VASP).

• Received 21 May 2009

DOI:https://doi.org/10.1103/PhysRevB.80.144403