Dresden 2017 – scientific programme
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MA: Fachverband Magnetismus
MA 41: Micromagnetism / Computational Magnetics
MA 41.1: Talk
Wednesday, March 22, 2017, 15:00–15:15, HSZ 101
Dynamics of skyrmions in chiral ferromagnets — •Stavros Komineas1,2 and Nikos Papanicolaou1 — 1University of Crete, Heraklion, Greece — 2RWTH Aachen University, 52056, Aachen, Germany
We give a description of the dynamics of topological and non-topological solitons in ferromagnetic films. We study materials with a Dzyaloshinskii-Moriya interaction and easy-axis anisotropy. Our analysis is based on an important link between topology and dynamics which is established through the construction of unambiguous conservation laws. In particular, we study the motion of a topological skyrmion with skyrmion number Q=1 and a non-topological skyrmionium with Q=0 under the influence of an applied field gradient (which plays the role of a force). The Q=1 skyrmion undergoes Hall motion perpendicular to the direction of the field gradient with a drift velocity proportional to the gradient. In contrast, the non-topological Q=0 skyrmionium is accelerated in the direction of the field gradient, thus exhibiting ordinary Newtonian motion. When the applied field is switched off the Q=1 skyrmion is spontaneously pinned around a fixed guiding center, whereas the Q=0 skyrmionium moves with constant velocity v. We give a numerical calculation of a skyrmionium traveling with any constant velocity v that is smaller than a critical velocity vc.