Theoretical seminar | 13 April 2022

The topological stabilization of chiral magnetic structures is discussed on the example of a two-dimensional magnetic skyrmion. The lifetime of a skyrmion is calculated based on the harmonic transition state theory. Localized magnetic models and models of itinerant magnetism are considered. A scaling theory has been developed for the lattice magnetic model. Using scaling relations derived from the continuous micromagnetic description, the parameters of the Hamiltonian corresponding to the exchange, anisotropy, and Dzyaloshinskii-Moriya interaction are chosen in such a way as to keep the energy of the skyrmion relative to the ground ferromagnetic state and its size unchanged. The number of magnetic moments included in the calculations reaches more than twenty millions. The evolution of the lifetime during the transition from a discrete to a continuous model, which reflects the "topological protection", is shown.

Main paper/arXiv, related to the seminar, and other references

1. P. F. Bessarab, G.P. Müller, I. S. Lobanov, F. N. Rybakov, N. S. Kiselev, H. Jónsson, V. M. Uzdin, S. Blügel, L. Bergqvist & A. Delin, Lifetime of racetrack skyrmions. Sci. rep., 8 (2018) 3433.
2. M.N. Potkina, I.S. Lobanov, H. Jónsson, and V.M. Uzdin. Skyrmions in antiferromagnets: Thermal stability and the effect of external field and impurities. J. Appl. Phys., 127 (2020), 213906.
3. M.N. Potkina, I.S. Lobanov, O.A. Tretiakov, H. Jonsson, V.M. Uzdin Stability of long-lived antiskyrmions in the Mn-Pt-Sn tetragonal Heusler material. Phys. Rev. B , 102 (2020) 134430.
4. И.С. Лобанов, М.Н. Поткина, В.М.Уздин, Устойчивость и времена жизни магнитных состояний нано- и микроструктур
(Миниобзор) Письма в ЖЭТФ, 113 (2021) 833.
5. I.S. Lobanov, V.M. Uzdin The lifetime of micron scale topological chiral magnetic states with atomic resolution,
Comp. Phys. Commun. 269 (2021) 108136