Bimerons create bimerons: proliferation and aggregation induced by currents and magnetic fields

TL;DR

This paper demonstrates how in-plane currents and magnetic fields can induce proliferation and aggregation of bimerons in a chiral magnet, leading to potential applications in bio-inspired spintronic devices.

Contribution

It reveals the conditions under which current-induced proliferation and aggregation of bimerons occur, including the roles of magnetic field, damping, and non-adiabatic torque, and describes the resulting lattice structures.

Findings

Proliferation and aggregation occur only with appropriate out-of-plane magnetic field.

Lower damping and larger non-adiabatic torque enhance bimeron proliferation.

Aggregates relax into a honeycomb lattice with defects after current injection.

Abstract

The aggregation of topological spin textures at nano and micro scales has practical applications in spintronic technologies. Here, the authors report the in-plane current-induced proliferation and aggregation of bimerons in a bulk chiral magnet. It is found that the spin-transfer torques can induce the proliferation and aggregation of bimerons only in the presence of an appropriate out-of-plane magnetic field. It is also found that a relatively small damping and a relatively large non-adiabatic spin-transfer torque could lead to more pronounced bimeron proliferation and aggregation. Particularly, the current density should be larger than a certain threshold in order to trigger the proliferation; namely, the bimerons may only be driven into translational motion under weak current injection. Besides, the authors find that the aggregate bimerons could relax into a deformed honeycomb bimeron lattice with a few lattice structure defects after the current injection. The results are promising for the development of bio-inspired spintronic devices that use a large number of aggregate bimerons. The findings also provide a platform for studying aggregation-induced effects in spintronic systems, such as the aggregation-induced lattice phase transitions.