Electromagnon excitations in modulated multiferroics

Abstract

The phenomenological theory of ferroelectricity in spiral magnets presented in [M. Mostovoy, Phys. Rev. Lett. 96, 067601 (2006)] is generalized to describe consistently states with both uniform and modulated-in-space ferroelectric polarizations. A key point in this description is the symmetric part of the magnetoelectric coupling since, although being irrelevant for the uniform component, it plays an essential role for the non-uniform part of the polarization. We illustrate this importance in generic examples of modulated magnetic systems: longitudinal and transverse spin-density wave states and planar cycloidal phase. We show that even in the cases with no uniform ferroelectricity induced, polarization correlation functions follow to the soft magnetic behavior of the system due to the magnetoelectric effect. Our results can be easily generalized for more complicated types of magnetic ordering, and the applications may concern various natural and artificial systems in condensed matter physics (e.g., magnon properties could be extracted from dynamic dielectric response measurements).

5 pages

References in corpus (12)

• Spin current and magneto-electric effect in non-collinear magnets
• Ferroelectricity in spiral magnets
• Role of the Dzyaloshinskii-Moriya interaction in multiferroic perovskites
• Multiferroics: different ways to combine magnetism and ferroelectricity
• Distorted Perovskite with e_g^1 Configuration as a Frustrated Spin System
• Possible evidence for electromagnons in multiferroic manganites
• Dynamical magneto-electric coupling in helical magnets
• Electromagnons in multiferroic YMn2O5 and TbMn2O5
• Erratum: Landau Analysis of the Symmetry of the Magnetic Structure and Magnetoelectric Interaction in Multiferroics [Phys. Rev. B 76, 05447 (2007)]
• Optical coupling to spin waves in the cycloidal multiferroic BiFeO3
• Colossal magnon-phonon coupling in multiferroic Eu${}_{0.75}$Y${}_{0.25}$MnO${}_3$
• Multiferroicity induced by dislocated spin-density waves

Cited by in corpus (9)

• Multiferroicity, The coupling between magnetic and polarization
• Polar phonons and spin excitations coupling in multiferroic BiFeO3 crystals
• Electric field control of magnon-induced magnetization dynamics in multiferroics
• Helical multiferroics for electric field controlled quantum information processing
• THz Magneto-electric atomic rotations in the chiral compound Ba${}_3$NbFe${}_3$Si${}_2$O${}_{14}$
• Dynamical magnetoelectric effects induced by the Dzyaloshinskii-Moriya interaction in multiferroics
• Electromagnon Resonances in the Optical Response of Spiral Magnets
• Pseudo-proper ferroelectricity in thin films
• Goldstone modes and electromagnon fluctuations in the conical cycloid state of a multiferroic