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MA: Fachverband Magnetismus

MA 1: Computational Magnetism I

MA 1.11: Vortrag

Montag, 16. März 2020, 12:15–12:30, HSZ 04

Quantum effects in thermally activated domain wall switching in ferromagnets. — •Grzegorz Kwiatkowski¹ and Pavel F. Bessarab^1,2 — ¹University of Iceland, Reykjavík, Iceland — ²Peter Grünberg Institute and Institute for Advanced Simulation, Forschungszentrum Jülich, Jülich, Germany

Most widely used data storage technologies are based on nanoscale magnetic structures [1]. In order to improve both memory retention and energy efficient writability one needs to increase stability of magnetic samples without changing the energy barrier. Therefore, it is vital to optimise the preexponential factor in the Arrhenius law, which requires one to properly study the effect of internal degrees of freedom on thermal switching pocesses [2,3]. We present analytic estimation of rate of escape for domain wall switching in 3D samples with focus on how results scale with internal parameters and sample size. Since minimum excitation energy for high frequency magnon modes is larger than average energy of thermal fluctuations, we employ Bose-Einstein statistics, which leads to nontrivial temperature dependencies of the preexponential factor. Our results open up new possibilities for enhancing stability of magnetic structures by entropic effects.

This work was funded by the Icelandic Reseach Fund (Grant No. 184949-052) and Alexander von Humboldt Foundation.

[1] W. A. Challener et al. Nat. Photon. volume 3 (2009)

[2] P. F. Bessarab et al. Phys. Rev. Lett. 110.2 (2013)

[3] G. Fiedler et al. J. Appl. Phys. 111 (2012)