Document type:
Zeitschriftenaufsatz
Author(s):
Wild, J.; Meier, T. N. G.; P̈ollath, S.; Kronseder, M.; Bauer, A.; Chacon, A.; Halder, M.; Schowalter, M.; Rosenauer, A.; Zweck, J.; M̈uller, J.; Rosch, A.; Pfleiderer, C.; Back, C. H.
Title:
Entropy-Limited Topological Protection of Skyrmions
Abstract:
Magnetic skyrmions are topologically protected whirls that decay through singular magnetic configurations known as Bloch points. We used Lorentz transmission electron microscopy to infer the energetics associated with the topological decay of magnetic skyrmions far from equilibrium in the chiral magnet Fe1-xCoxSi. We observed that the lifetime $\tau$ of the skyrmions depends exponentially on temperature, $<$img class="highwire-embed" alt="Embedded Image" src="http://advances.sciencemag.org/sites/default/files/highwire/advances/3/9/e1701704/embed/mml-math-1.gif"/$>$. The prefactor $\tau$0 of this Arrhenius law changes by more than 30 orders of magnitude for small changes of the magnetic field, reflecting a substantial reduction of the lifetime of skyrmions by entropic effects and, thus, an extreme case of enthalpy-entropy compensation. Such compensation effects, being well known across many different scientific disciplines, affect topological transitions and, thus, topological protection on an unprecedented level. Entropic effects counteract the topological protection of magnetic skyrmions, leading to faster decay rates than expected. Entropic effects counteract the topological protection of magnetic skyrmions, leading to faster decay rates than expected.
Journal title: