Stefan Blügel

Title

Chiral magnetic skyrmions in ultrathin films and heterostructures: Insights from materials-specific theory

Abstract

"Ultrathin magnetic films and heterostructures provide a fantastic playground for the stabilization, manipulation and usage of magnetic skyrmions – topological magnetization solitons – magnetic entities described by a micromagnetic energy functional with particle like properties that may open a new vista for spintronics. A crucial quantity for the chiral skyrmion formation is the Dzyaloshinskii-Moriya interaction (DMI), whose presence in thin films could be established in a concerted effort of first-principles theory and spin-polarized scanning tunnelling microscopy [1]. It could be shown that the spin-orbit interaction and the structure inversion-asymmetry in these systems result in a DMI that is strong enough to give rise to one-dimensional and two-dimensional lattices [2] of chiral spin-textures as well as chiral domain walls [3]. Even single skyrmions [4] could be induced. In retrospect, it is surprising how little is known about the DMI in these metallic systems. In this talk I give some insight into the DMI, relating first-principles calculations of the DMI in thin films and MnFeGe alloys [5] to different models [6] and discuss possibilities to tailor the magnetic interactions to enlarge the materials base to stabilize single skyrmions in films and heterostructures. The chiral bobber [6] is introduced an interesting three-dimensional hybrid particle consisting of skyrmion and a monopole.

References

[1] M. Bode et al., Nature 447, 190 (2007). [2] S. Heinze et al., Nature Physics 7, 713 (2011). [3] M. Heide et al., Phys. Rev. B. 78, 140403(R) (2008). [4] N. Romming et al., Science 341, 636 (2013). [5] J. Gayles et al., Phys. Rev. Lett. 91, 245123 (2015). [6] V. Kashid et al., Phys. Rev. B. 90, 054412 (2014). [6] F. N. Rybakov et al., Phys. Rev. Lett. accepted, arXiv:1508.04786