title: Observation of magnetic excitations of Skyrmion crystal in a helimagnetic insulator Cu2OSeO3.
abstract: We have investigated the low-energy dynamics of the triangular lattice of Skyrmions in a helimagnetic insulator Cu2OSeO3 in terms of microwave response. We have observed two elementary excitations of the Skyrmion with different polarization characteristics: the counterclockwise circulating mode at 1 GHz with the magnetic field polarization parallel to the Skyrmion plane and the breathing mode at 1.5 GHz with a perpendicular magnetic field polarization. These modes reflect the topological nature of Skyrmions and may play a central role in the Skyrmion dynamics.
authors.affiliation: Department of Applied Physics and Quantum Phase Electronics Center (QPEC), University of Tokyo, Tokyo 113-8656, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Onose
authors.forename: Y
authors.initials: Y
authors.lastname: Okamura
authors.forename: S
authors.initials: S
authors.lastname: Seki
authors.forename: S
authors.initials: S
authors.lastname: Ishiwata
authors.forename: Y
authors.initials: Y
authors.lastname: Tokura