Dresden 2017 – scientific programme
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MA: Fachverband Magnetismus
MA 64: Poster 1
MA 64.2: Poster
Friday, March 24, 2017, 09:30–13:00, P2-EG
The Influence of the Dzyaloshinskii-Moriya (DM) interactions on the magnon spectrum in Cu2OSeO3 — •Y. Onykiienko1, Y. Tymoshenko1, D. Inosov1, P. Portnichenko1, A. Schneidewind2, P. Cermak2, A. Henschel3, and M. Schmidt3 — 1Institute of Solid State Physics, TU Dresden, D-01069 Dresden, Germany — 2Jülich Center for Neutron Science (JCNS), Garching, Germany — 3Max Planck Institute for Chemical Physics of Solids, Dresden, German
Cu2OSeO3 is an insulating helimagnetic multiferroic material which hosts a skyrmion phase. It has non-centrosymmetric space group (P213) similar to the B20 skyrmion compounds (e.g. MnSi, FeGe), but with a much more complex structure. Recent studies reveal good agreement between TOF neutron scattering data and theoretical predictions that suggest a spin model with up to 5 nearest-neighbor Heisenberg exchange interactions neglecting antisymmetric DM terms responsible for the helical ground state. Taking them into account leads to corrections that are smaller than the resolutions of most available instruments. However a significant deviation has been found in the spin-wave spectrum, presumably, caused by the DM interactions.
By means of the cold neutron TAS we observed the gap of about 1.6 meV in the magnetic spectrum which is absent in the previously reported spin-wave model. In addition we established magnon branch splitting at high symmetry points of the reciprocal space. Both observations can be explained in the frame of the linear spin-wave theory by taking into account theoretically predicted DM interactions.