Current-driven dynamics of magnetic skyrmions in an ultrathin film: experiments and modelling

Roméo Juge, Soong-Geun Je, Dayane de Souza Chaves, Liliana D. Buda-Prejbeanu, José Peña-Garcia, Jayshankar Nath, Ioan Mihai Miron, Kumari Gaurav Rana, Lucia Aballe, Michael Foerster, Francesca Genuzio, Tevfik Onur Menteş, Andrea Locatelli, Francesco Maccherozzi, Sarnjeet S. Dhesi, Mohamed Belmeguenai, Yves Roussigné, Stéphane Auffret, Stefania Pizzini, Gilles Gaudin, Jan Vogel, Olivier Boulle

Published 2019-04-17Version 1

Magnetic skyrmions are chiral spin textures which hold great promise as nanoscale information carriers. Their recent observation at room temperature and their fast current-induced manipulation in multiple repetitions of heavy metal/ferromagnetic stacks have lifted an important bottleneck towards the practical realisation of skyrmion-based devices. However, the complex spin textures and large power dissipation in these multilayers limit their practical implementation as well as the fundamental understanding of the skyrmion dynamics. Here, we report on the current-driven motion of skyrmions in an ultrathin Pt/Co/MgO model system. We find that skyrmions with diameters in the 100 nm range can move at speeds up to 100 m.s$^{-1}$. Our experiments also reveal that the skyrmion Hall effect is markedly drive-dependent. These observations are well substantiated both by a simple analytical model and micromagnetic simulations, which highlight the important role of pinning in the skyrmion dynamics.