Investigation of Sub-configurations Reveals Stable Spin-Orbit Torque Switching Polarity in Polycrystalline Mn3Sn

TL;DR

This study investigates how the polycrystalline structure of Mn3Sn influences spin-orbit torque switching, revealing stable switching polarity in certain configurations and clarifying the physical mechanisms behind robust SOT switching.

Contribution

It introduces a comprehensive analysis of polycrystalline Mn3Sn, demonstrating the impact of atomic orientation on SOT-induced switching and establishing a dynamic balance model for understanding the phenomena.

Findings

Configuration II exhibits robust, stable SOT switching.

Sub-configurations in Configuration I cancel each other out.

The polycrystalline nature is crucial for understanding SOT behavior.

Abstract

Previous studies have demonstrated the switching of octupole moment in Mn3Sn driven by spin-orbit torque (SOT). However, they have not accounted for the polycrystalline nature of the sample when explaining the switching mechanism. In this work, we use samples with various atomic orientations to capture this polycrystalline nature. We thoroughly investigate their SOT-induced spin dynamics and demonstrate that the polycrystalline structure leads to distinct outcomes. Our findings reveal that configuration II, where the Kagome plane is perpendicular to the spin polarization, exhibits robust switching with stable polarity, whereas the signals from various sub-configurations in configuration I cancel each other out. By comparing our findings with experimental results, we pinpoint the primary sources contributing to the measured AHE signals. Additionally, we establish a dynamic balance model that incorporates the unique properties of Mn3Sn to elucidate these observations. Our study highlights the essential role of the polycrystalline nature in understanding SOT switching. By clarifying the underlying physical mechanisms, our work resolves the longstanding puzzle regarding the robust SOT switching observed in Mn3Sn.