Magneto-optical spectra of epitaxial ferromagnetic MnAs films grown on Si and GaAs substrates

Abstract
We have studied magnetic circular dichroism (MCD) spectra of ferromagnetic MnAs epitaxial thin films of (1̄101), (1̄100), and (0001) crystallographic growth orientations. The films were grown on Si(001), Si(111), GaAs(001), and GaAs(111)B substrates by molecular-beam epitaxy. We have found strong crystal orientation dependence of MCD spectra of MnAs films in terms of characteristic features and absolute intensity of MCD signals. We have also measured temperature dependence of MCD spectra on a (0001) MnAs film. Features at low temperatures are found to be different from those at room temperature. Our experimental results are compared with the ionic model for the electronic structure of NiAs-type MnAs and with magneto-optical Kerr ellipticity spectra recently calculated using an all electron full potential linear muffin-tin orbital method.