PhD project description:

Magnetic skyrmions are two-dimensional (2D) topological magnetic textures that hold promise as information carriers in ultradense memory and logic devices owing to their small size, robustness and the extremely low spin-polarized currents needed to move them¹. This project aims to explore, understand and achieve control of the dynamics of such nanoscale spin configurations when confined in nanostructures. Magnetic skyrmions exhibit rich behaviour governed by their topology, such as the basic gyrotropic and breathing eigenmodes². While very recent advances have brought the static manipulation of skyrmions under control, their dynamical behaviour is largely unexplored experimentally. The first observation of the basic eigenmode dynamics of skyrmion bubbles was only recently demonstrated³.

The student will use state-of-the art dynamical X-ray imaging to unravel nanoscale and sub-nanosecond information on skyrmion dynamical phenomena. The measurements take place in large-scale facilities (i) Swiss Light Source, Paul Scherrer Institute, CH, ii) Advanced Light Source, Berkeley, USA, iii) BESSY, Berlin, DE). A second part of this project will be the use of advanced computational approaches (micromagnetic simulations) to systematically explore the underlying Physics of topological objects in magnetism.

Research work will focus on lithographically defined nanostructures where skyrmions can be isolated, propagated and manipulated. This research project provides a wide range of learning experience: A) Nanofabrication, B) Measurement using X-Rays techniques, C) Micromagnetic simulations and data analysis.

In short this project will make a leading-edge contribution to understanding the fundamental physics of room temperature magnetic skyrmions⁴ and enable their manipulation in applications. Their ultra small size and the comparatively ultra low current to move them makes them highly promising for next generation spintronics applications with storage and logic operations. This can offer a route to more power efficient devices with a considerable impact in our increasingly technological world, where energy management is paramount.

References

¹ A. Fert, V. Cros, J. Sampaio, Nature Nanotechnology 8, 152 (2013)

² C. Moutafis, S. Komineas, J.A.C. Bland, Phyical Review B 79, 224429 (2009)

³ F. Büttner, C. Moutafis, et. al, Nature Physics 11, 225 (2015)

⁴ C. Moreau-Luchaire, C. Moutafis, et al., Nature Nanotechnology, 11, 444 (2016)