Dresden 2017 – scientific programme

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MA: Fachverband Magnetismus

MA 47: Spin Hall Effects and Skyrmions I

MA 47.2: Talk

Thursday, March 23, 2017, 09:45–10:00, HSZ 04

Crossover between mechanisms of skyrmion annihilation in a racetrack — •Pavel Bessarab¹, Igor Lobanov², Gideon Müller³, Filipp Rybakov⁴, Nikolai Kiselev³, Stefan Blügel³, Lars Bergqvist⁵, and Anna Delin⁵ — ¹University of Iceland, Reykjavík, Iceland — ²ITMO University, St. Petersburg, Russia — ³Forschungszentrum Jülich, Jülich, Germany — ⁴Institute of Metal Physics, Ekaterinburg, Russia — ⁵KTH Royal Institute of Technology, Kista, Sweden

Theoretical calculations of thermal stability of skyrmions in a PdFe bilayer strip on an Ir(111) substrate are presented. The lifetime of a skyrmion at a given temperature is identified using harmonic transition state theory for spins [1]. The energy barriers are obtained from minimum energy paths (MEPs) for skyrmion annihilation and pre-exponential factors are estimated from the curvature of the energy surface. The MEP calculations [2] revealed two mechanisms of skyrmion annihilation in the strip: escape through the boundary and radial collapse at the interior. At low external fields, the escape mechanism prevails, but a crossover field exists, above which the collapse mechanism becomes dominant, defining the skyrmion stability. This analysis provides a deeper understanding of skyrmion formation and stability and helps develop ways to control magnetic skyrmions in novel devices.

[1] P.F. Bessarab, V.M. Uzdin, H. Jónsson, Phys. Rev. B, 85, 184409 (2012).

[2] P.F. Bessarab, V.M. Uzdin, H. Jónsson, Comput. Phys. Commun., 196, 335 (2015).