Significant spin polarization of Co2MnGa Heusler thin films on MgO(100) measured by ultraviolet photoemission spectroscopy

Abstract

The spin dependent valence band structure of the Heusler compound Co2MnGa grown on MgO(100) is investigated by spin resolved ultraviolet photoemission spectroscopy (SRUPS). Using a vacuum suitcase, epitaxial thin film samples are transferred from a deposition chamber into an SRUPS chamber with a highly efficient spin detector. The transport results only in weak oxidation of the moderately reactive compound Co2MnGa. A spin polarization of 34% is obtained at the Fermi energy. The energy dependence of the spin polarization including a sign change at E−EF=−0.6 eV is in good agreement with theoretical predictions of the bulk properties of the Heusler compound.