Spin-orbit interaction in combination with structural inversion asymmetry on magnetic surfaces, interfaces, heterostructures and nanostructures is a source of a variety of spin-dependent transport phenomena and novel magnetic textures, the chiral magnetic skyrmions [1] being the best known. In this presentation I display our effort to optimize magnetic nanostructures for skyrmions [2-7] in a potential race-track memory application. I discuss the issues of skyrmion size, life time [8] and detection [9, 10]. If time permits, I also discuss further localized particles such as bobbers [11] and antiskyrmions [12] for alternatives in race-track applications. 

Our investigations make use of a multiscale approach based on (i) density-functional theory (FLAPW method as implemented in the FLEUR code [13] and the Korringa-Kohn-Rostoker method as implemented in juKKR [14]) combined with (ii) atomistic spindynamics code SPIRIT [15] by which the lifetime of the skyrmions are determined combining the Geodesic Nudged Elastic Band method (GNEB) [16] or the Systematic Saddle Point Search method [17] with the harmonic transition state theory, and (iii) micromagnetic reasoning.

We acknowledge funding by EU-H2020 project MAGicSky (No 665095), DARPA TEE program (#HR0011831554) from DOI, as well as computing time from JARA-HPC and Jülich Supercomputing Centre.

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[13] For a program description, see www.flapw.de.
[14] For a program description, see https://jukkr.fz-juelich.de.
[15] For a program description, see https://spirit-code.github.io.
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[17] Gideon P. Müller et al., Phys. Rev. Lett. 121, 197202 (2018).