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MA: Fachverband Magnetismus

MA 18: Topological Defects in Magnetic Materials: from Devices to Cosmos
(PhD-Student Symposium jointly with jDPG)

MA 18.3: Vortrag

Dienstag, 12. März 2013, 10:30–10:45, H16

Rotating skyrmion lattices by spin torques and field or temperature gradients — •Karin Everschor-Sitte^1,2, Markus Garst², Benedikt Binz², Florian Jonietz¹, Sebastian Mühlbauer³, Christian Pfleiderer¹, and Achim Rosch² — ¹Physik-Department E21, Technische Universität München — ²Institut für Theoretische Physik, Universität zu Köln — ³Forschungsneutronenquelle Heinz Maier Leibnitz (FRM II), Technische Universität München

Chiral magnets like MnSi form lattices of skyrmions, i.e., magnetic whirls, which react sensitively to small electric currents j above a critical current density j_c. The interplay of these currents with tiny gradients of either the magnetic field or the temperature can induce a rotation of the magnetic pattern for j>j_c. Either a rotation by a finite angle of up to 15^∘ or – for larger gradients – a continuous rotation with a finite angular velocity is induced. We use Landau-Lifshitz-Gilbert equations extended by extra damping terms in combination with a phenomenological treatment of pinning forces to develop a theory of the relevant rotational torques [1]. Experimental neutron scattering data on the angular distribution of skyrmion lattices suggest that continuously rotating domains are easy to obtain in the presence of remarkably small currents and temperature gradients.
[1] K. Everschor et al., PRB 86, 054432 (2012)