Magnetic Phase Dependence of the Anomalous Hall Effect in Mn$_3$Sn Single Crystals

TL;DR

This study investigates how magnetic phase transitions in Mn$_3$Sn single crystals influence the anomalous Hall effect, demonstrating that the effect can be turned on or off by changes in magnetic symmetry.

Contribution

It reveals the magnetic phase dependence of the anomalous Hall effect in Mn$_3$Sn and shows how magnetic symmetry changes control the AHE.

Findings

AHE is suppressed below 275 K coinciding with magnetic phase change.

Magnetization measurements identify two magnetic phase transitions.

The large AHE can be switched off by magnetic symmetry changes.

Abstract

Thermodynamic and transport properties are reported on single crystals of the hexagonal antiferromagnet Mn$_3$Sn grown by the Sn flux technique. Magnetization measurements reveal two magnetic phase transitions at $T_1$ = 275 K and $T_2$ = 200 K, below the antiferromagnetic phase transition at $T_N$ $\approx$ 420 K. The Hall conductivity in zero magnetic field is suppressed dramatically from 4.7 $\Omega^{-1}$cm$^{-1}$ to near zero below $T_1$, coincident with the vanishing of the weak ferromagnetic moment. This illustrates that the large anomalous Hall effect (AHE) arising from the Berry curvature can be switched on and off by a subtle change in the symmetry of the magnetic structure near room temperature.