Dresden 2017 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 64: Poster 1

MA 64.2: Poster

Freitag, 24. März 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.