Current-induced Dynamics of Bloch Domain-wall Bimerons

TL;DR

This paper investigates the current-driven dynamics of domain-wall bimerons in ferromagnets, revealing how spin current orientation affects their motion and providing insights for spintronic device applications.

Contribution

It systematically analyzes the effects of spin-transfer and spin-orbit torques on bimeron dynamics, highlighting anisotropic responses and the impact of bimeron chain length.

Findings

Bimeron Hall effect enables efficient motion with perpendicular spin currents.

Parallel spin currents suppress transverse motion and reduce the Hall angle.

Increasing bimeron number decreases their collective mobility.

Abstract

Domain-wall bimerons are composite topological structures formed by embedding bimerons within domain walls in ferromagnets with in-plane anisotropy. These hybrid textures have recently attracted significant attention due to their promise for racetrack memory applications. In this work, we systematically investigate the current-driven dynamics of single domain-wall bimerons and bimeron chains under spin-transfer torque (STT) and spin-orbit torque (SOT). We show that when the spin current is injected or polarized perpendicular to the domain wall, the bimeron Hall effect facilitates efficient motion along the wall. In contrast, spin currents injected or polarized parallel to the wall suppress transverse motion, leading to a significant reduction in the bimeron Hall angle. This anisotropic response is observed for both STT and SOT driving mechanisms. Furthermore, we find that increasing the number of bimerons within a domain wall diminishes their collective mobility. These results provide key insights into domain-wall bimeron dynamics and offer guidance for their integration into bimeron-based spintronic devices.