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Center for Nonlinear Studies |
Chiral magnets like MnSi, Fe1-xCoxSi, or Cu2OSeO3 gain Dzyaloshinskii-Moriya spin-orbit energy by twisting the magnetization on a long length scale giving rise to spatially modulated magnetic textures like helices and skyrmion crystals. The spin-wave excitations exhibit Bragg scattering of these textures resulting in a magnon band structure in accordance with Bloch’s theorem. We first discuss the magnetic resonances that probe the magnon spectrum at zero momentum. While the helix supports two resonances, there are three resonances within the skyrmion crystal corresponding to two gyration modes and a breathing mode [1]. In the second part, we elaborate on the magnon excitations at finite momenta [2] that have been recently resolved in the helimagnetic phase with the help of inelastic neutron scattering [3].
[1] T Schwarze, J Waizner, Markus Garst, A Bauer, I Stasinopoulos, H. Berger, Christian Pfleiderer, and D Grundler, Nature Materials 14, 478 (2015).
[2] C. Schütte and M. Garst, Phys Rev B 90, 094423 (2014).
[3] M. Kugler, G. Brandl, J. Waizner, M. Janoschek, R. Georgii, A. Bauer, K. Seemann, A. Rosch, C. Pfleiderer, P. Böni, and M. Garst, arXiv: 1502.06977.
This colloquium talk and and Markus’s visit at LANL are supported by Institute fore Material Science (IMS) at LANL. Markus is visiting LANL from 08/24 to 09/04. If you would like to discuss with Markus during his visit please contact Marc Janoschek (mjanoschek@lanl.gov) and the IMS administrator Caryll Blount (caryll@lanl.gov).
Host: Marc Janoschek