Epitaxial thin films of Mn3-x Cox Ga were grown on MgO by magnetron co-sputtering with different Co content. Dependent on the Co content tetragonal or cubic structures are obtained. The composition dependence of saturation magnetization MS and uniaxial magnetic anisotropy Ku in the epitaxial films were investigated. A high magnetic anisotropy Ku of 1.2 MJ m-3 was achieved for the Mn 2.6Co0.3Ga1.1 film with low magnetic moment of 0.84 μB. The valence band spectra of the films were investigated mainly by hard x-ray photoelectron spectroscopy. The evidence of sharp states in the cubic case, which are smeared out in the tetragonal case, proof the existence of a van Hove singularity that causes a band Jahn-Teller effect accompanied by a tetragonal distortion. These differences are in well agreement to the ab-initio calculations of the electronic structure.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)