SKM 2023 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 23: Poster Magnetism I

MA 23.6: Poster

Dienstag, 28. März 2023, 17:00–19:00, P1

Thermal skyrmion diffusion with alternating current excitations — •Tobias Sparmann, Raphael Gruber, Jan Rothörl, Maarten A. Brems, Fabian Kammerbauer, and Mathias Kläui — Department of Physics, Johannes-Gutenberg University Mainz

Magnetic skyrmions are considered promising candidates for implementing probabilistic computing devices since they respond strongly nonlinearly to external stimuli and feature multiscale dynamics [1].

The implementation of such probabilistic computing relies on thermal excitation and diffusive movement of the magnetic skyrmions within thin films, which exhibit pinning due to sample defects [2]. Especially the combination of skyrmion diffusion and current-induced motion has been shown to be useful in Brownian reservoir computing devices [3]. As thermal skyrmion diffusion is often slow due to the impact of pinning, a depinning procedure using the already present electric excitation of the skyrmions can be key for applications.

To reach such a regime of very high diffusion, we propose and experimentally demonstrate depinning by applying alternating currents to the sample [4]. In particular, we show that the energy landscape is effectively flattened and diffusion drastically enhanced for sufficient current densities. This can therefore be useful to reduce pinning effects and accelerate non-conventional computing devices.

[1] D. Prychynenko et al., Phys. Rev. Applied, 9, 014034 (2018).

[2] J. Zázvorka et al., Nat. Nanotechnol., 14, 658 (2019).

[3] R. Gruber et al., Nat. Comm., 13, 3144 (2022).

[4] T. Sparmann et al., in preparation (2022).