Sinusoidal electromagnon in RMnO3: Indication of anomalous magnetoelectric coupling

Abstract

The optical spectra in the family of multiferroic manganites RMnO3 is a great puzzle. Current models can not explain the fact that two strong electromagnons are present in the non-collinear spin cycloidal phase, with only one electromagnon surviving the transition into the collinear spin sinusoidal phase. We show that this is a signature of the presence of anomalous magnetoelectric coupling that breaks rotational invariance in spin space and generates oscillatory polarization in the ground state.

5 pages, 2 figures

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• Role of the Dzyaloshinskii-Moriya interaction in multiferroic perovskites
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Cited by in corpus (7)

• Spin and lattice excitations of a BiFeO3 thin film and ceramics
• Electromagnon in the Z-type hexaferrite $({\mathrm{Ba}}_x{\mathrm{Sr}}_{1-x}{)}_3\mathrm{C}{\mathrm{o}}_2\mathrm{F}{\mathrm{e}}_{24}{\mathrm{O}}_{41}$
• Possible coupling between magnons and phonons in multiferroic CaMn7O12
• Magnetic order and electromagnon excitations in DyMnO3 studied by neutron scattering experiments
• Electromagnon in ferrimagnetic eps-Fe2O3 nanograin ceramics
• Spin-wave dispersion and magnon chirality in multiferroic TbMnO3
• Modifying the magnetoelectric coupling in TbMnO${}_3$ by low-level Fe${}^{3+}$ substitution