Exciting skyrmions in chiral magnets
15.07.2014 at 11:00
Chiral magnets, encompassing the metal MnSi, the semiconductor Fe1-xCoxSi and the insulator Cu2OSeO3, gain Dzyaloshinskii-Moriya spin-orbit energy by twisting the magnetization on a long length scale resulting in spatially modulated magnetic skyrmion textures. The topological nature of these objects gives rise to various interesting phenomena like a topological Hall effect, a Skyrmion-flow Hall effect and spin-torque effects at ultralow threshold currents. This presentation focusses on the excitations of magnetic skyrmions and their interaction with spin-waves. After a short discussion of the magnetic resonances within the skyrmion lattice phase , we theoretically explore the excitation modes of a single skyrmion and its magnon scattering cross section. Due to the skyrmion topology, the magnons are skew scattered which leads to a magnon Hall effect. The magnons also transfer momentum to the skyrmion, and we discuss the resulting effective Thiele equation of motion . Our results provide, in particular, the basis for a theory of skyrmion caloritronics for a dilute skyrmion gas in clean insulating chiral magnets.
 T. Schwarze, J. Waizner, M. Garst, A. Bauer, I. Stasinopoulos, H. Berger, C. Pfleiderer and D. Grundler, submitted to Nature Materials.
 C. Schütte and M. Garst, submitted to Phys. Rev. B. [arXiv:1405.1568]
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