Engineering magnetic skyrmions at transition-metal multilayers
Bertrand Dupé (Institute of Theoretical Physics and Astrophysics, University of Kiel)

Due to their unique topological and dynamic properties skyrmions in magnetic materials offer attractive perspectives for future spintronic applications [1]. Recently, it has been discovered that magnetic skyrmions of Néel-type symmetry cannot only occur in ultra-thin transition metal films at surfaces [2,3] but also in asymmetric multilayers due to strong Dzyaloshinskii-Moriya (DMI) interactions [4]. We carry out first-principles calculations in order to study the stabilization mechanism of skyrmions from ultrathin films to multilayers and we predict the emergence of skyrmions in a new class of multilayers based on [4d/Fe2/5d]n, i.e. structures composed of Fe biatomic layers sandwiched between 4d- and 5d-transition-metal layers [5]. In these composite structures, the exchange and the Dzyaloshinskii-Moriya interactions, which control skyrmion formation, can be tuned separately by the two interfaces. This allows engineering skyrmions as shown by density functional theory, Monte Carlo and spin dynamics simulations.
[1] A. Fert, et al., Nature Nano. 8, 152 (2013).
[2] N. Romming, et al., Science 341, 636 (2013).
[3] B. Dupé, et al., Nature Comm. 5, 4030 (2014).
[4] C. Moreau-Luchaire, et al., Nature Nano. (2016) doi: 10.1038/nnano.2015.
[5] B. Dupé, et al., accepted in Nature Comm. (arXiv :1503.08098).