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MA: Fachverband Magnetismus
MA 37: Skyrmions III
MA 37.6: Talk
Thursday, March 21, 2024, 10:45–11:00, EB 301
Multipole magnons in topological skyrmion lattices resolved by cryogenic Brillouin light scattering microscopy — •Riccardo Ciola1, Ping Che2, Markus Garst1, Volodymyr Kravchuk1, Arnaud Magrez2, Helmuth Berger2, Thomas Schönenberger2, Henrik Rønnow2, and Dirk Grundler2 — 1Karlsruhe Institute of Technology, Germany — 2École Polytechnique Fédérale de Lausanne, Switzerland
Chiral magnets provide an innovative framework to study non-collinear spin textures and their associated magnetization dynamics. They include helical and conical magnetic textures that are spatially modulated with a wavevector kh as well as the topologically non-trivial skyrmion lattice (SkL) phase. Their spin waves have been explored in the long-wavelength regime using resonance and spin wave spectroscopy, and in the short wavelength regime using inelastic neutron scattering. Here, we show that Brillouin light scattering (BLS) is ideally suited to probe the complementary range of wavevectors k ≤ kh. We analysed bulk spin waves in the SkL phase of Cu2OSeO3. We provide parameter-free predictions for the corresponding resonances and their spectral weights. The theoretical results are compared to a BLS experiment in the backscattering geometry that probe magnons with a wavevector k=48rad/µ m < kh = 105rad/µ m. The clockwise, counterclockwise and breathing modes are resolved. Due to the finite wavevector of the magnon excitations, finite spectral weight is theoretically predicted also for other resonances. Experimentally, at least one additional resonance with quadrupole character is identified.
Keywords: Skyrmions; Brillouin light scattering; Magnonics