Regensburg 2019 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 34: Magnetic textures: Transport and dynamics II
MA 34.5: Vortrag
Mittwoch, 3. April 2019, 16:15–16:30, H37
Dynamics in confined skyrmion ensembles on different time scales — •Alexander F. Schäffer1, Levente Rózsa2, Jamal Berakdar1, and Elena Y. Vedmedenko2 — 1Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, D-06099 Halle (Saale), Germany — 2Institut für Nanostruktur- und Festkörperphysik, Universität Hamburg, D-20355 Hamburg, Germany
In this study, ensembles of magnetic skyrmions on confined geometries are shown to exhibit characteristic temperature driven motion on two different time-scales. The intrinsic fluctuating dynamics (t∼ 1 ns) is governed by short-ranged symmetric and antisymmetric exchange interaction, whereas the long-time limit (t10 ns) is determined by the coaction of skyrmion-skyrmion-repulsion and the system’s geometry.
Full micromagnetic simulations along with quasiparticle model Monte Carlo calculations for realistic island shapes and sizes are performed and analyzed, indicating the special importance of skyrmion dynamics at finite temperatures including skyrmion-skyrmion and skyrmion-boundary repulsion effects.
Our results highlight the conflict between skyrmion-mobility and finite observation times, directly affecting the addressability of skyrmionic bits, which is a key challenge on the path of developing skyrmion-based room-temperature applications.
The presented quasiparticle Monte Carlo approach bears great potential for a computationally effective description of the diffusive motion of skyrmion ensembles on finite geometries like racetrack memory setups.