Calculations of spin-induced transport in ferromagnets

Based on first-principles density functional calculations, a general approach for determining and analyzing the degree of spin polarization (P) in ferromagnets is presented. The approach employs the so-called tetrahedron method to evaluate the Fermi surface integrations of P in both ballistic and diffusive regimes. The validity of the method is examined by comparing the calculated P values for Fe and Ni with the experiment. The method is shown to yield highly accurate results with minimal computational effort. Within our approach, it is also possible to systematically analyze the contributions of various types of electronic states to the spin-induced transport. As a case study, the transport properties of the soft-ferromagnet CeMn Ni4 are investigated in order to explain the origin of the existing difference between the experimental and theoretical values of P in this intermetallic compound.