Skyrmion-Bimeron Transformation in Bilayer Chiral Magnets with Competing Magnetic Anisotropy

TL;DR

This paper explores how topological spin textures like skyrmions and bimerons emerge and transform in bilayer chiral magnets, revealing new phases and stabilization mechanisms through Monte Carlo simulations.

Contribution

It demonstrates the continuous transformation from skyrmions to bimerons driven by magnetic anisotropy changes in bilayer systems, providing a systematic topological map.

Findings

Multiple magnetic configurations identified, including labyrinths, skyrmion lattices, and meron phases.

Interlayer exchange coupling stabilizes topological cores and increases defect energy.

Transformation from skyrmions to bimerons occurs with anisotropy variation.

Abstract

In this work, we investigate the emergence of topological spin textures in a ferromagnetically coupled bilayer chiral magnet by means of Monte Carlo simulations of a classical spin model including exchange interaction, Dzyaloshinskii-Moriya interaction, magnetic anisotropy, and an external magnetic field. To characterize the topology of the system, we construct a scalar chirality map in the $(K/J,h/J)$ parameter space. Our results reveal several magnetic configurations, including labyrinth structures, skyrmion lattices, ferromagnetic states, and meron-antimeron crystal phases. In particular, we show that the transition from easy-axis to easy-plane anisotropy drives a continuous transformation from skyrmion textures to bimeron-type configurations. The bilayer geometry introduces an additional stabilization mechanism, where interlayer exchange coupling correlates the topological cores in the two layers and increases the energetic cost of defect collapse. These findings provide a systematic topological texture map for bilayer chiral magnets and highlight coupled magnetic layers as a promising platform for stabilizing bimeron-type spin textures in nanoscale spintronic systems.