Confinement of Magnetic Skyrmions to Corrals of Artificial Surface Pits with Complex Geometries

Abstract

Magnetic skyrmion is a particle-like swirling spin texture promising for future memory devices. The geometric confinement and artificial control of skyrmions are crucial for such practical applications. In a previous research, we developed a technique to confine skyrmions to simple geometric corrals, such as a rectangle and a triangle, composed of artificial surface pits with nanometer-scale dimensions fabricated by using a focused electron beam. The technique has a potential advantage of facilitating more complex geometries, which has not been fully explored yet. Here we directly visualize skyrmions confined to surface-pit corrals with several complex geometries by using differential phase contrast scanning transmission electron microscopy. We find that individual skyrmions are deformed not only in shape but also in size under a moderate-bias field. We also find that deformed skyrmionic spin textures with opposite polarities coexist in the zero-field condition. The present study provides a guide to confine skyrmions, which should be useful for future applications.

Geometric phase analysis of magnetic skyrmion lattices in Lorentz transmission electron microscopy images

“…We also hope that this method will be useful to study skyrmion lattices in samples of different geometries as in Ref. 40,41 for example. As the skyrmion lattice tend to align with the edges of the sample, geometric constraints could lead to different arrangements with different deformation fields.…”

Geometric phase analysis of magnetic skyrmion lattices in Lorentz transmission electron microscopy images

“…We also hope that this method will be useful to study skyrmion lattices in samples of different geometries as in Ref. [37,38] for example. As the skyrmion lattice tend to align with the edges of the sample, geometric constraints could lead to different arrangements with different deformation fields.…”

Room-Temperature Zero-Field kπ-Skyrmions and Their Field-Driven Evolutions in Chiral Nanodisks

“…Confined geometry is an effective approach for regulating magnetic structures. ,, In particular, skyrmions can be stabilized without an external magnetic field because this strategy utilizes the shape anisotropy induced by the magnetic dipole interaction in confined systems. − Additional boundary conditions are essential for the survival of the target skyrmion. Although the target skyrmion and its extension of kπ- skyrmions have been theoretically predicted, ,− their experimental observation has been limited to low temperatures in the chiral magnet FeGe ( k = 2) .…”

“…22,23 Confined geometry is an effective approach for regulating magnetic structures. 15,24,25 In particular, skyrmions can be stabilized without an external magnetic field because this strategy utilizes the shape anisotropy induced by the magnetic dipole interaction in confined systems. 26−31 Additional boundary conditions are essential for the survival of the target skyrmion.…”