Berlin 2015 – wissenschaftliches Programm
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KR: Fachgruppe Kristallographie
KR 4: Multiferroics I (DF jointly with DS, KR, MA, TT)
KR 4.10: Vortrag
Mittwoch, 18. März 2015, 12:00–12:15, EB 107
Magon-phonon interactions in hexagonal multiferroic YMnO3 — •Andreas Kreisel1, Shantanu Mukherjee1, Brian M. Andersen1, Turi Schäffer1, Sonja Holm1, Kim Lefmann1, Niels C.R. Momsen1, Jacob Larsen2, Amy Fennell3, Uwe Stuhr3, and Zahra Yamani4 — 1Niels Bohr Institute, University of Copenhagen, Denmark — 2Institute of Physics, Technical University of Denmark — 3Laboratory of Neutron Scattering, Paul Scherrer Institute, Switzerland — 4Chalk River National Laboratory, Canada
The multiferroic material YMnO3 is known to show a large spin lattice coupling such that the spin and lattice degrees of freedom influence various properties, as for example the thermal conductivity that is found to have an anomalous contribution. The magnetoelastic modes have been measured recently in neutron diffraction experiments and linked to certain spectral features in Raman signals. Starting from a Heisenberg model on a triangular lattice with single ion anisotropies, we investigate the spin-phonon coupling via the magnetostriction mechanism and derive a coupled magnon-phonon model valid in the entire Brillouin zone. Within a spin-wave approach, where the coupling yields a hybrid magnon-phonon mode, we calculate the dynamic structure factor and compare to recent experimental neutron results.