Robust formation of skyrmion and skyrmionium in magnetic hemispherical shells and their dynamic switching

Jaehak Yang, Hyeon-Kyu Park, Gyuyoung Park, Claas Abert, Dieter Suess, Sang-Koog Kim

We explored the variations of the topological magnetic textures of vortices, skyrmions, and skyrmioniums in magnetic elements of hemispherical-shell shape with respect to surface-normal uniaxial magnetic anisotropy constant Ku, Dzyaloshinskii-Moriya interaction (DMI) constant Dint, and shell diameter 2R. For given values of 2R, the combination of Ku and Dint plays a crucial role in the stabilization of those different spin textures. With decreasing 2R, the geometrical confinement of hemispherical shells more significantly affects the stabilization of skyrmions owing to curvature-induced DM-like interaction. This effect is contrastingly dependent on the sign of Dint: skyrmion formation is more favorable for positive Dint values, whereas it is less favorable for negative ones. A quite promising feature is that skyrmions can be stabilized even in the absence of intrinsic DMI for 2R < 25 nm. We also explored characteristic dynamic properties of skyrmions excited by in-plane and out-ofplane oscillating magnetic fields. Similarly to the fundamental dynamic modes found in planar dots, in-plane gyration and azimuthal spin-wave modes as well as out-of-plane breathing modes were found, but additional higher-frequency hybrid modes also appeared due to coupling between radially quantized and azimuthal spinwave modes. Finally, we found a switching behavior of skyrmion polarity through a transient skyrmionium state using very-low-strength AC magnetic fields. This work provides further physical insight into the static and dynamic properties of skyrmions in curved-geometry nanodots and suggests potential applications to low-powerconsumption and ultra-high-density information-storage devices.

Physics of Functional Materials, Research Platform MMM Mathematics-Magnetism-Materials
External organisation(s)
Seoul National University (SNU)
Physical Review B
No. of pages
Publication date
Peer reviewed
Austrian Fields of Science 2012
103017 Magnetism, 103018 Materials physics
ASJC Scopus subject areas
Electronic, Optical and Magnetic Materials, Condensed Matter Physics
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