Berlin 2018 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 9: Magnetic domain walls
MA 9.5: Vortrag
Montag, 12. März 2018, 16:00–16:15, EB 202
A numerical study on ferrimagnetic domain wall motion in temperature gradients — •Andreas Donges1, Unai Atxitia2, Thomas Schönenberger3, Severin Selzer1, and Ulrich Nowak1 — 1Fachbereich Physik, Universität Konstanz, DE-78457 Konstanz, Germany — 2Fachbereich Physik, Freie Universität Berlin, DE-14195 Berlin, Germany — 3École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
We investigate the domain wall (DW) dynamics of a typical rare earth-transition metal ferrimagnet in a constant temperature gradient using atomistic Langevin dynamics simulations based on the stochastic Landau-Lifshitz-Gilbert equation. Our results are compared to the ferro- and antiferromagnetic DW motion which have been studied more thoroughly so far [1,2]. Surprisingly, below the angular momentum compensation temperature TA, we find a regime in which the DW is moving towards the colder region, i.e. against Schlickeiser’s entropic torque [1] which suggests a drift into the hotter region. Recently, Moretti et al. [3] showed that such a reversed DW motion might be connected to spin wave reflections. Furthermore, our simulations suggest the existence of a torque compensation point TT>TA, at which the DW precession changes sign. This also implies that a DW propagating along such a temperature gradient can undergo two Walker breakdowns: one above and one below TT.
[1] F. Schlickeiser, et al., Phys.Rev.Lett. 113, 097201 (2014)
[2] S. Selzer, et al., Phys.Rev.Lett. 117, 107201 (2016)
[3] S. Moretti, et al., Phys.Rev.B 95, 064419 (2017)