Spin polarization ratios of resistivity and density of states estimated from anisotropic magnetoresistance ratio for nearly half-metallic ferromagnets

We derive a simple relational expression between the spin polarization ratio of resistivity, P-rho, and the anisotropic magnetoresistance ratio Delta rho/rho, and that between the spin polarization ratio of the density of states at the Fermi energy, P-DOS, and Delta rho/rho for nearly half-metallic ferromagnets. We find that P-rho and P-DOS increase with increasing |Delta rho/rho| from 0 to a maximum value. In addition, we roughly estimate P-rho and P-DOS for a Co2FeGa0.5Ge0.5 Heusler alloy by substituting its experimentally observed Delta rho/rho into the respective expressions. (C) 2016 The Japan Society of Applied Physics