Phason mode of electromagnons in terbium manganite with sinusoidal antiferromagnetic structure

The interaction of light with electromagnons in a sinusoidally modulated antiferromagnetic phase of TbMnO3 is examined. It is predicted that the frequency dependence of the dielectric tensor epsilon(zz) changes substantially at the transition from a sinusoidal into a spiral magnetic phase with spontaneous electric polarization. The phason mode of such a transition is an electromagnon mode in which the magnetoelectric phase is due to modulation of the magnetic structure. (c) 2007 American Institute of Physics.