Topological meron-antimeron domain walls and skyrmions in a low-symmetry system

TL;DR

This study explores how low-symmetry bcc(110) systems can host various topological magnetic structures, including domain walls and skyrmions, with potential for spin-texture engineering in spintronics.

Contribution

It demonstrates the formation of topologically trivial and non-trivial domain walls, merons, and skyrmions in a low-symmetry system using combined experimental and theoretical methods.

Findings

Topological domain walls depend on crystallographic direction.

Holes facilitate transition to spin-spiral states.

Magnetic fields can transform domain walls into skyrmions.

Abstract

The generation of topologically non-trivial magnetic configurations has been a pivotal topic in both basic and applied nanomagnetism research. Localized non-coplanar magnetic defects such as skyrmions or merons were found to interact strongly with currents, making them interesting candidates for future spintronics applications. Here, we study a low-symmetry bcc(110) system by spin-polarized scanning tunneling microscopy and an atomistic spin model using parameters obtained from first-principles calculations. We demonstrate how a delicate balance between energy terms generates both topologically trivial and non-trivial domain walls, depending on their crystallographic direction. The topological walls consist of merons and antimerons and the topological charge amounts to about 0.2/nm wall length. The incorporation of holes in the films facilitates the transition from an in-plane ferromagnetic ground state to a spin-spiral state. Both domain walls and spirals transition into isolated elongated magnetic skyrmions in applied magnetic fields, establishing low-symmetry systems as a versatile platform for spin-texture engineering.