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

TL;DR

This study combines experimental and theoretical approaches to demonstrate that antisite disorder in Co2FeAl Heusler compounds enhances the Berry curvature, leading to a significant intrinsic anomalous Hall effect with potential spintronics applications.

Contribution

It provides new insights into how atomic disorder influences Berry phase effects and the anomalous Hall conductivity in Co2FeAl Heusler compounds.

Findings

Experimental AHC of 227 S/cm at 2 K

Intrinsic AHC of 155 S/cm with temperature independence

Disorder enhances Berry curvature and intrinsic AHE

Abstract

Co2-based Heusler compounds are the promising materials for the spintronics application due to their high Curie temperature, large spin-polarization, large magnetization density, and exotic transport properties. In the present manuscript, we report the anomalous Hall effect (AHE) in a polycrystalline Co2FeAl Heusler compound using combined experimental and theoretical studies. The Rietveld analysis of high-resolution synchrotron x-ray diffraction data reveals a large degree (~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 Co2FeAl is governed by the Berry phase driven intrinsic mechanism. Our theoretical calculations reveal that the disorder present in Co2FeAl compound enhances the Berry curvature induced intrinsic AHC.