High spin polarization of the anomalous Hall current in Co-based Heusler compounds

Based on first principles density functional calculations of the intrinsic anomalous and spin Hall conductivities, we predict that the charge Hall current in Co-based full Heusler compounds Co2XZ (X = Cr and Mn; Z = Al, Si, Ga, Ge, In and Sn), except Co2CrGa, would be almost fully spin polarized, even though Co2MnAl, Co2MnGa, Co2MnIn and Co2MnSn do not have a half-metallic band structure. Furthermore, the ratio of the associated spin current to the charge Hall current is slightly larger than 1.0. This suggests that these Co-based Heusler compounds, especially Co2MnAl, Co2MnGa and Co2MnIn which are found to have large anomalous and spin Hall conductivities, might be called anomalous Hall half-metals and could have valuable applications in spintronics such as spin valves as well as magnetoresistive and spin-torque-driven nanodevices. These interesting findings are discussed in terms of the calculated electronic band structures, magnetic moments and also anomalous and spin Hall conductivities as a function of the Fermi level. (paper)