Manipulating the Topology of Nanoscale Skyrmion Bubbles by Spatially Geometric Confinement

TL;DR

This paper demonstrates that spatial geometric confinement can stabilize skyrmion bubbles in centrosymmetric magnets, reducing the required magnetic field for nucleation and controlling their topological properties, advancing skyrmion-based memory applications.

Contribution

It introduces a method of using geometric confinement to selectively stabilize skyrmion bubbles and suppress trivial or metastable bubbles in centrosymmetric magnets.

Findings

Geometric confinement stabilizes skyrmion bubbles.

Critical magnetic field for nucleation is reduced by an order of magnitude.

Dipole-dipole interactions influence skyrmion topological transitions.

Abstract

The discovery of magnetic skyrmion bubbles in centrosymmetric magnets has been receiving increasing interest from the research community, due to the fascinating physics of topological spin textures and its possible applications to spintronics. However, key challenges remain, such as how to manipulate the nucleation of skyrmion bubbles to exclude the trivial bubbles or metastable skyrmion bubbles that usually coexist with skyrmion bubbles in the centrosymmetric magnets. Here, we report having successfully performed this task by applying spatially geometric confinement to a centrosymmetric frustrated Fe3Sn2 magnet. We demonstrate that the spatially geometric confinement can indeed stabilize the skyrmion bubbles, by effectively suppressing the formation of trivial bubbles and metastable skyrmion bubbles. We also show that the critical magnetic field for the nucleation of the skyrmion bubbles in the confined Fe3Sn2 nanostripes is drastically less, by an order of magnitude, than that what is required in the thin plate without geometrical confinement. By analyzing how the width and thickness of the nanostripes affect the spin textures of skyrmion bubbles, we infer that the topological transition of skyrmion bubbles is closely related to the dipole-dipole interaction, which we find is consistent with theoretical simulations. The results presented here represent an important step forward in manipulating the topological spin textures of skyrmion bubbles, making us closer to achieving the fabrication of skyrmion-based racetrack memory devices.