Regensburg 2010 – scientific programme

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DF: Fachverband Dielektrische Festkörper

DF 4: Multiferroics I (Joint Session of MA, DF, KR, DS)

DF 4.7: Talk

Monday, March 22, 2010, 12:00–12:15, H3

Evidence of electro-active excitation of the spin cycloid in TbMnO₃ — •Alexey Shuvaev¹, Viktor Travkin², Vsevolod Ivanov², Alexander Mukhin², and Andrei Pimenov¹ — ¹Experimentelle Physik 4, Universität Würzburg, D-97074 Würzburg, Germany — ²General Physics Institute, Russian Academy of Science, 119991 Moscow, Russia

The coupling between the magnetic and ferroelectric orders in multiferroics is currently a topic of intense study. The materials of particular interest are those where the incommensurate cycloidal ordering of the spins drives the ferroelectricity. One of the consequences of multiferroicity is the existence of novel coupled magnon-phonon excitations called electromagnons. In addition to the electromagnon along the a-axis, the polarization analysis of the experimental spectra suggests the existence of an electro-active excitation for ac electric fields along the crystallographic c-axis. This excitation is possibly the electro-active eigenmode of the spin cycloid in TbMnO₃, which has been predicted within the inverse Dzyaloshinskii-Moriya mechanism of magnetoelectric coupling.