Piezomagnetic switching of anomalous Hall effect in an antiferromagnet at room temperature

TL;DR

This study demonstrates that small uniaxial strain can control the anomalous Hall effect in a room-temperature antiferromagnetic metal, revealing a large piezomagnetic effect with potential spintronics applications.

Contribution

It reports the first observation of large room-temperature piezomagnetism in a metallic antiferromagnet, enabling control of the anomalous Hall effect independently of magnetization.

Findings

Small uniaxial strain controls the sign and magnitude of AHE.

Piezomagnetism in Mn3Sn is significant at room temperature.

Control of AHE is distinct from magnetization effects.

Abstract

Piezomagnetism couples strain linearly to magnetic order producing magnetization. Thus, unlike magnetostriction, it enables bidirectional control of a net magnetic moment. If this effect becomes large at room temperature, it may be technologically relevant, similar to its electric analogue, piezoelectricity. To date, however, the studies of the piezomagnetic effect have been primarily restricted to antiferromagnetic (AF) insulators at cryogenic temperatures. Here we report the discovery of a large piezomagnetism in a metal at room temperature. Strikingly, by using the AF Weyl semimetal Mn$_3$Sn, known for its nearly magnetization-free anomalous Hall effect (AHE), we find that an application of small uniaxial strain of the order of 0.1 % can control both the sign and size of the AHE. Our experiment and theory show that the piezomagnetism can control the AHE distinctly from the magnetization, which will be useful for spintronics applications.