A Frustrated Bimeronium: Static Structure and Dynamics

TL;DR

This paper introduces the concept of bimeronium, a topological spin texture in in-plane magnetized magnets, analyzing its static structure and dynamics under spin-orbit torques, with potential applications in spintronics.

Contribution

It presents the first detailed study of bimeronium structures, including their static properties and behavior under spin-orbit-torque-induced dynamics.

Findings

Bimeronium is a topological counterpart of skyrmionium.

Steady rotation occurs when spin polarization aligns with the easy axis.

Bimeronium can be annihilated when spin polarization is perpendicular to the easy axis.

Abstract

We show a topological spin texture called "bimeronium" in magnets with in-plane magnetization. It is a topological counterpart of skyrmionium in perpendicularly magnetized magnets and can be seen as a combination of two bimerons with opposite topological charges. We report the static structure and spin-orbit-torque-induced dynamics of an isolated bimeronium in a magnetic monolayer with frustrated exchange interactions. We study the anisotropy and magnetic field dependences of a static bimeronium. We also explore the bimeronium dynamics driven by the damping-like spin-orbit torque. We find that the bimeronium shows steady rotation when the spin polarization direction is parallel to the easy axis. Moreover, we demonstrate the annihilation of the bimeronium when the spin polarization direction is perpendicular to the easy axis. Our results are useful for understanding fundamental properties of bimeronium structures and may offer an approach to build bimeronium-based spintronic devices.