Geometrically constrained Skyrmions

Abstract

Skyrmions are chiral swirling magnetization structures with nanoscale size. These structures have attracted considerable attention due to their topological stability and promising applicability in nanodevices, since they can be displaced with spin-polarized currents. However, for the comprehensive implementation of skyrmions in devices, it is imperative to also attain control over their geometrical position. Here we show that, through thickness modulations introduced in the host material, it is possible to constrain three-dimensional skyrmions to desired regions. We investigate skyrmion structures in rectangular FeGe platelets with micromagnetic finite element element simulations. First, we establish a phase diagram of the minimum-energy magnetic state as a function of the external magnetic field strength and the film thickness. Using this understanding, we generate preferential sites for skyrmions in the material by introducing dot-like "pockets" of reduced film thickness. We show that these pockets can serve as pinning centers for the skyrmions, thus making it possible to obtain a geometric control of the skyrmion position. This control allows stabilizing skyrmions at positions and in configurations that they would otherwise not attain. Our findings may have implications for technological applications in which skyrmions are used as units of information that are displaced along racetrack-type shift register devices.

12 pages, 4 figures

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Cited by in corpus (4)

• Statics and Dynamics of Skyrmions Interacting with Pinning: A Review
• Deterministic Generation and Guided Motion of Magnetic Skyrmions by Focused He${}^{+}$-Ion Irradiation
• Skyrmion pinning by disk-shaped defects
• Robust and programmable logic-in-memory devices exploiting skyrmion confinement and channeling using local energy barriers