Confinement of Skyrmions in Nanoscale FeGe Device-like Structures

TL;DR

This study investigates how nanoscale device geometries influence skyrmion confinement and behavior in FeGe, revealing that complex shapes enable skyrmion formation at lower magnetic fields, which is promising for low-energy data storage applications.

Contribution

It demonstrates that complex device geometries significantly affect skyrmion formation and stability, offering new ways to control skyrmions in nanoscale devices.

Findings

Complex geometries enable skyrmion formation at lower magnetic fields.

Device shape influences skyrmion position and number.

Skyrmion behavior differs between simple and complex structures.

Abstract

Skyrmion-containing devices have been proposed as a promising solution for low energy data storage. These devices include racetrack or logic structures and require skyrmions to be confined in regions with dimensions comparable to the size of a single skyrmion. Here we examine Bloch skyrmions in FeGe device shapes using Lorentz transmission electron microscopy (LTEM) to reveal the consequences of skyrmion confinement in a device-like structure. Dumbbell-shaped elements were created by focused ion beam (FIB) milling to provide regions where single skyrmions are confined adjacent to areas containing a skyrmion lattice. Simple block shapes of equivalent dimensions were also prepared to allow a direct comparison with skyrmion formation in a less complex, yet still confined, device geometry. The impact of applying a magnetic field and varying the temperature on the formation of skyrmions within the shapes was examined. This revealed that it is not just confinement within a small device structure that controls the position and number of skyrmions, but that a complex device geometry changes the skyrmion behaviour, including allowing skyrmions to form at lower applied magnetic fields than in simple shapes. This could allow methods to be developed to control both the position and number of skyrmions within device structures.