Dresden 2020 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 57: Skyrmions IV (joint session MA/TT)

TT 57.5: Talk

Thursday, March 19, 2020, 10:30–10:45, POT 6

Skyrmion size and shape within continuous magnetization model and atomistic spin model — •Anastasiia S. Varentsova^1,2 and Pavel F. Bessarab^1,2,3 — ¹ITMO University, St. Petersburg, Russia — ²University of Iceland, Reykjavík, Iceland — ³Peter Grünberg Institute and Institute for Advanced Simulation, Forschungszentrum Jülich, Jülich, Germany

We explore the relationship between two approaches to the description of skyrmions in magnetic materials. One of the approaches involves characterization of magnetic states by a continuous magnetization field. Within the other approach, magnetic structures are represented by magnetic moments localized on vertices of a discrete lattice. By tracing contours of constant skyrmion size in the material parameter space, we demonstrate that the continuous magnetization model and the lattice model agree quite well for large skyrmions with smooth profiles, but predict different results for small skyrmions and skyrmions with bubble-like shape. We propose to link the two models by a material parameter transformation that does not rely on the assumption of small spatial variation of the magnetic structure on the scale of the lattice constant. As a result, good agreement between the continuous magnetization theory and the lattice model can be obtained for the whole skyrmion sector of the magnetic phase diagram.

This work was funded by the Russian Science Foundation (Grant No. 19-72-10138), the Icelandic Reseach Fund (Grant No. 184949-052) and Alexander von Humboldt Foundation.