Berlin 2018 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 10: Skyrmions I (joint session MA/KFM/TT)
MA 10.4: Vortrag
Montag, 12. März 2018, 16:00–16:15, EB 301
Entropy limited topological protection of skyrmions in Fe1−xCoxSi — Johannes Wild1, •Thomas Meier1, Simon Pöllath1, Matthias Kronseder1, Andreas Bauer2, Alfonso Chacon2, Marco Halder2, Marco Schowalter3, Andreas Rosenauer3, Josef Zweck1, Jan Müller4, Achim Rosch4, Christian Pfleiderer2, and Christian Back1 — 1Institut für experimentelle und angewandte Physik, Universität Regensburg — 2Physik-Department, Technische Universität München — 3Institut für Festkörperphysik, Universität Bremen — 4Institut für Theoretische Physik, Universität zu Köln
Topologically protected magnetic textures in materials with broken inversion symmetry are considered as future high-density data storage media. The life time of these textures therefore plays a crucial role for data retention. We have used Lorentz transmission electron microscopy to infer the energetics of the topological decay of magnetic skyrmions far from equilibrium in the chiral magnet Fe1−x Cox Si. We investigated the decay of a lattice of sykrmions at different magnetic fields and temperatures by imaging the magnetic configuration of the system in real-time with a high speed camera. We observed that the skyrmion life time τ extracted from these movies depends exponentially on temperature following an Arrhenius law, τ ∝ τ0 exp(Δ E/kB T). The prefactor τ0 of this Arrhenius law changes by more than 30 orders of magnitude for small changes of magnetic field reflecting a substantial reduction of the life time of skyrmions by entropic effects and thus an extreme case of enthalpy-entropy compensation.