Extrinsic suppression of anomalous Hall effect in Fe-rich kagome magnet Fe3Sn

TL;DR

This study demonstrates that increasing Fe content in Fe3Sn kagome magnets suppresses extrinsic contributions to the anomalous Hall effect, allowing the intrinsic component to dominate and align with theoretical predictions, thus offering a method to control AHE.

Contribution

The paper reveals that Fe enrichment suppresses extrinsic AHE contributions in Fe3Sn, highlighting the role of spin-orbit coupling strength in skew scattering suppression, and aligns experimental AHC with theoretical values.

Findings

Extrinsic AHE is greatly suppressed in Fe-rich Fe3Sn.

Intrinsic AHE approaches the predicted 555 S/cm across temperatures.

Spin-orbit coupling strength of impurities influences skew scattering suppression.

Abstract

In Fe-based kagome magnets, Fe3Sn has been predicted to have the largest intrinsic anomalous Hall conductivity (AHC) and the highest Curie temperature TC = 743 K. However, the current experimental results show that the total AHC is much lower than the predicted value due to the strong extrinsic contribution. To suppress the extrinsic contribution and thus enhance the intrinsic contribution, we increased the Fe content in the stoichiometric Fe3Sn. We found that the extrinsic contribution is greatly suppressed, and the intrinsic contribution is dominant and is close to the theoretically predicted value of 555 S/cm over the whole temperature range. Based on the formula of the skew scattering, we analyzed the reason why the skew scattering is suppressed and found that the spin-orbit coupling strength provided by the impurity center is the key. The spin-orbit coupling strength provided by Fe as an impurity center in this study is much smaller than that of Sn as an impurity center in previous studies. Therefore, the AHC in Fe-rich Fe3Sn obeys the unified theory, while the AHC in Sn-rich Fe3Sn deviates from the unified theory. Our study provides a promising solution for the regulation of the extrinsic contribution to the anomalous Hall effect in kagome magnets.