Systematic parameter study of magnetic skyrmions and antiskyrmions stabilised by exchange interactions

It is a major ongoing task to optimize the thermal stability of magnetic skyrmions (Sk) and antiskyrmions (ASk), which is in particular limited for sub-10 nm Sk and ASk in 2D magnetic materials. In contrast to previous studies [1], we do not focus on a stabilisation of Sk and ASk by Dzyaloshinskii-Moriya interaction (DMI) but by exchange frustration [2] and higher order exchange interactions (HOI) [3]. We explore the large interaction parameter space of the atomistic Heisenberg model, consisting of exchange interaction beyond nearest neighbours, DMI, magnetocrystalline anisotropy and HOI by means of highly automatised energetic optimisation and geodesic nudged elastic band method (GNEB) simulations. Here we present the resulting sizes and energy barriers for SK and ASK in ferromagnetic and antiferromagnetic lattices with hexagonal and square geometry. In contrast to past, more anecdotally studies of the effect of exchange frustration [2,4] and HOI [3], this enables us to identify systematically the areas of parameters space in which metastable Sk and ASk can exist and how much their energy barriers can be enhanced in the framework of the atomistic extended Heisenberg model beyond nearest neighbours.

[1] A. S. Varentcova, S. von Malottki et al., NPJ Comput. Mat. 6, 193 (2020)

[2] S. von Malottki et al., Sci. Rep. 7, 12299 (2017)

[3] S. Paul, S. Haldar, S. von Malottki et al., Nat. Commun. 11, 4756 (2020)

[4] M. Hoffmann et al., Phys. Rev. Lett. 124, 247201 (2020)