Spin polarization of Mn$_5$Ge$_3$ in the bulk and thin films

The intermetallic compound Mn$_5$Ge$_3$ is one of the promising materials for application as a source of charge carriers in spintronics. The existing experimental data on the spin polarization in Mn$_5$Ge$_3$ demonstrate significant discrepancies. All theoretical studies concern a Mn$_5$Ge$_3$ bulk crystal. At the same time, thin films are of interest for applications. In this work, ab initio calculations have been performed for a Mn$_5$Ge$_3$ thin film on a germanium substrate. The difference between the magnetic moments of manganese atoms, densities of states, and spin polarizations for the bulk crystal and thin film has been demonstrated.