Special CMSM Seminar by Prof. Mathias Kläui, Johannes Gutenberg-Universität Mainz, Germany.

In our information-everywhere society IT is a major player for energy consumption. Novel spintronic devices can play a role in the quest for GreenIT if they are stable and can transport and manipulate spin with low power. Firstly to obtain ultimate stability, topologically stabilized spin structures, such as chiral domain walls and skyrmions can be used [1-3]. We have investigated in detail their dynamics and find that it is governed by the topology of their spin structures [1]. By designing the materials, we can even obtain a skyrmion lattice phase as the ground state of the thin films [2]. Secondly, for ultimately efficient spin manipulation, we use spin-orbit torques: we combine ultimately stable skyrmions with spin orbit torques into a skyrmion racetrack device [2,3], where the real time imaging of the trajectories allows us to quantify the novel skyrmion Hall effect [3]. Thirdly we use ferroic insulators for efficient spin transport [4] including spin superfluidity [5].

 

[1] F. Büttner et al., Nature Phys. 11, 225 (2015).

[2] S. Woo et al, Nature Mater. 15, 501 (2016).

[3] K. Litzius et al., Nature Phys. 13, 170 (2017).

[4] S. Geprägs et al., Nature Commun. 7, 10452 (2016); J. Cramer et al. Nature Commun (in press).

[5] Y. Tserkovnyak and M. Kläui, Phys. Rev. Lett. 119, 187705 (2017).