Effect of Electron-Phonon Scattering on the Anomalous Hall Conductivity of Fe$_3$Sn: A Kagome Ferromagnetic Metal

TL;DR

This study investigates how electron-phonon scattering affects the anomalous Hall conductivity in Fe$_3$Sn, revealing temperature-dependent extrinsic contributions and confirming electron-phonon interactions through resistivity behavior.

Contribution

It provides the first detailed analysis of electron-phonon scattering's impact on anomalous Hall conductivity in a Kagome ferromagnetic metal, highlighting the temperature dependence of extrinsic effects.

Findings

Intrinsic Hall conductivity is temperature independent at 485±60 S/cm.

Extrinsic Hall conductivity decreases with temperature following a specific relation.

Electron-phonon scattering is confirmed by linear resistivity dependence on temperature.

Abstract

We report on magnetic and magnetotransport studies of a Kagome ferromagnetic metal, Fe$_3$Sn. Our studies reveal a large anomalous Hall conductivity ($\sigma_{zx}$) in this system, mainly contributed by temperature independent intrinsic Hall conductivity ($\sigma^{int}_{zx}$=485$\pm$60 S/cm) and temperature dependent extrinsic Hall conductivity ($\sigma^{ext}_{zx}$) due to skew-scattering. Although $\sigma^{ext}_{zx}$ value is large and almost equivalent to the intrinsic Hall conductivity at low temperatures, it drastically decreases with increasing temperature, following the relation $\sigma^{ext}_{zx}=\frac{\sigma_{zx0}^{ext}}{(aT+1)^2}$, under the influence of electron-phonon scattering. The presence of electron-phonon scattering in this system is also confirmed by the linear dependence of longitudinal electrical resistivity at higher temperatures [$\rho(T)\propto T$]. We further find that Fe$_3$Sn is a soft ferromagnet with an easy-axis of magnetization lying in the $\it{ab}$ plane of the crystal with magnetocrystalline anisotropy energy density as large as 1.02 $\times$ 10$^6$