Atomic disorder and Berry phase driven anomalous Hall effect in a Co2FeAl Heusler compound

Abstract

${\mathrm{Co}}_{2}$-based Heusler compounds are promising materials for spintronics applications due to their high Curie temperature, large spin polarization, large magnetization density, and exotic transport properties. In the present paper, we report the anomalous Hall effect (AHE) in a polycrystalline ${\mathrm{Co}}_{2}\mathrm{FeAl}$ Heusler compound using combined experimental and theoretical studies. The Rietveld analysis of high-resolution synchrotron x-ray diffraction data reveals a large degree $(\ensuremath{\sim}50%)$ of antisite disorder between Fe and Al atoms. The analysis of anomalous transport data provides the experimental anomalous Hall conductivity (AHC) about 227 S/cm at 2 K with an intrinsic contribution of 155 S/cm, which has nearly constant variation with temperature. The detailed scaling analysis of anomalous Hall resistivity suggests that the AHE in ${\mathrm{Co}}_{2}\mathrm{FeAl}$ is governed by the Berry phase driven intrinsic mechanism. Our theoretical calculations reveal that the disorder present in the ${\mathrm{Co}}_{2}\mathrm{FeAl}$ compound enhances the Berry curvature induced intrinsic AHC.