Entropy-limited topological protection of skyrmions.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 28975152.
- Also identified by DOI 10.1126/sciadv.1701704 and PMC identifier 5621974.
- Licence recorded as CC BY-NC.
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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 Fe<sub>1-<i>x</i></sub> Co <sub><i>x</i></sub> Si. We observed that the lifetime τ of the skyrmions depends exponentially on temperature, [Formula: see text]. The prefactor τ<sub>0</sub> 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.