Imprinting electrically switchable scalar spin chirality by anisotropic strain in a Kagome antiferromagnet

TL;DR

This study shows how anisotropic strain in Mn₃Sn thin films can induce a switchable scalar spin chirality, leading to room-temperature anomalous Hall effects and multi-stable memory states for spintronic devices.

Contribution

It introduces a novel method of manipulating magnetic ground states in Mn₃Sn via anisotropic strain, enabling electrically switchable spin chirality and enhanced spintronic functionalities.

Findings

Anisotropic strain reduces symmetry from C₃v to C₁ in Mn₃Sn.

Strain induces out-of-plane canting of Mn spins.

Room-temperature anomalous Hall effect observed due to scalar spin chirality.

Abstract

Topological chiral antiferromagnets, such as Mn$_{3}$Sn, are emerging as promising materials for next-generation spintronic devices due to their intrinsic transport properties linked to exotic magnetic configurations. Here, we demonstrate that anisotropic strain in Mn$_{3}$Sn thin films offers a novel approach to manipulate the magnetic ground state, unlocking new functionalities in this material. Anisotropic strain reduces the point group symmetry of the manganese (Mn) Kagome triangles from $C_{3v}$ to $C_{1}$, significantly altering the energy landscape of the magnetic states in Mn$_{3}$Sn. This symmetry reduction enables even a tiny in-plane Dzyaloshinskii-Moriya (DM) interaction to induce canting of the Mn spins out of the Kagome plane. The modified magnetic ground state introduces a finite scalar spin chirality and results in a significant Berry phase in momentum space. Consequently, a large anomalous Hall effect emerges in the Kagome plane at room temperature - an effect that is absent in the bulk material. Moreover, this two-fold degenerate magnetic state enables the creation of multiple-stable, non-volatile anomalous Hall resistance (AHR) memory states. These states are field-stable and can be controlled by thermal assisted current-induced magnetization switching requiring modest current densities and small bias fields, thereby offering a compelling new functionality in Mn$_{3}$Sn for spintronic applications.