Edge-Mediated Skyrmion Chain and Its Collective Dynamics in a Confined Geometry

TL;DR

This paper reports the first experimental observation of skyrmion chains in FeGe nanostripes, revealing edge-mediated formation and collective dynamics, which could inform future skyrmion-based memory devices.

Contribution

It provides the first experimental evidence of edge-mediated skyrmion chain formation and their collective motion in nanostripes, expanding understanding of skyrmion behavior in confined geometries.

Findings

Skyrmion chains form at edges under magnetic field.

Skyrmions move collectively into the nanostripe center at higher fields.

Skyrmion chains persist in wider nanostripes.

Abstract

The emergence of a topologically nontrivial vortex-like magnetic structure, the magnetic skyrmion, has launched new concepts for memory devices. There, extensive studies have theoretically demonstrated the ability to encode information bits by using a chain of skyrmions in one-dimensional nanostripes. Here, we report the first experimental observation of the skyrmion chain in FeGe nanostripes by using high resolution Lorentz transmission electron microscopy. Under an applied field normal to the nanostripes plane, we observe that the helical ground states with distorted edge spins would evolves into individual skyrmions, which assemble in the form of chain at low field and move collectively into the center of nanostripes at elevated field. Such skyrmion chain survives even as the width of nanostripe is much larger than the single skyrmion size. These discovery demonstrates new way of skyrmion formation through the edge effect, and might, in the long term, shed light on the applications.