Dresden 2017 – wissenschaftliches Programm
MA 61.2: Vortrag
Freitag, 24. März 2017, 09:45–10:00, HSZ 401
Isolated skyrmion dynamics in confined helimagnetic nanostructures — •Marijan Beg1, David I. Cortés-Ortuño1, Weiwei Wang1,2, Rebecca Carey1, Mark Vousden1, Ondrej Hovorka1, and Hans Fangohr1 — 1Faculty of Engineering and the Environment, University of Southampton, Southampton, SO17 1BJ, United Kingdom — 2Department of Physics, Ningbo University, Ningbo, 315211, China
Understanding the dynamic response of skyrmionic states is of importance both from the aspect of fundamental physics as well as for their manipulation. We explore the isolated skyrmion ground state dynamics in a 150 nm diameter FeGe disk sample at zero external magnetic field using a full three-dimensional model, which includes the demagnetisation energy and does not make any assumptions about the translational invariance of magnetisation in the out-of-film direction. We compute all existing eigenmodes employing the eigenvalue method, and then, using the ringdown method we determine which eigenmodes can be excited using two different experimentally feasible excitations (in-plane and out-of-plane). Finally, we investigate how the resonant frequencies change when the external magnetic bias field and the disk sample diameter are varied. We observe the existence of only one gyrotropic and one breathing low-frequency eigenmode, and the field-dependent power spectral density maps suggest that the gyrotropic eigenmode is the reversal mode of an isolated skyrmion state. This work was supported by the EPSRC’s EP/G03690X/1 and EP/N032128/1 grants and the Horizon 2020 European Research Infrastructure project (676541).