Regensburg 2019 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 34: Magnetic textures: Transport and dynamics II

MA 34.10: Vortrag

Mittwoch, 3. April 2019, 17:45–18:00, H37

Skyrmion diffusion in thin film multilayers — •Markus Weißenhofer, Andreas Donges, and Ulrich Nowak — Fachbereich Physik, Universität Konstanz, Universitätsstraße 10, DE-78457 Konstanz, Germany

While being of fundamental interest as the type of diffusion yields information on transport and dissipation processes, thermally activated diffusion processes can also serve as a sensitive tool to analyze system properties. We use the stochastic Landau-Lifshitz-Gilbert equation to simulate diffusive motion of Skyrmions in a (Pt0.95Ir0.05)/Fe-bilayer on a Pd(111) surface. Here, the frustration of the isotropic exchange interactions in connection with the Dzyaloshinskii-Moriya interaction is responsible for the creation of skyrmionic structures [1]. We demonstrate the validity of the existing analytical theory for diffusive motion in flat energy landscapes [2] by calculating the diffusion coefficient for Skyrmions with different topological charges finding a linear temperature dependence as analytically expected [3]. Simulations at low temperatures reveal that in this system skyrmionic structures which are deformed by the Dzyaloshinskii-Moriya interaction show anisotropic diffusive behaviour in combination with rotational brownian motion in a weak periodic potential. Furthermore we quantitatively investigate this rotational energy landscape for deformed skyrmions and determine the mean rotation time for different temperatures [1].

[1] Rózsa et al., Phys. Rev. B 95, 094423 (2017). [2] Schütte et al., Phys. Rev. B 90, 174434 (2014). [3] Zázvorka et al., arXiv:1805.05924 [cond-mat.mtrl-sci]