The interest in multiferroic materials has increased in the last few years due to the fundamental physics of strong interaction between ferroelectric and magnetic orders, as well as for the promise of novel applications in future electronics. From powerful symmetry arguments and with modeling of the microscopic coupling mechanism, these efforts have led to the discovery of a vast set of multiferroic compounds. An important recent step in this regard was the discovery of a new kind of magnetic excitation that couples strongly to light by acquiring electric dipole activity from the infrared active phonons, called electromagnon, which is a hybrid excitation of magnon and phonon character. These discoveries have highlighted the importance of the dynamical aspects of the magnetoelectric coupling.

Based on measurements of the electrodynamic spectra as function of temperature and magnetic field in multiferroic RMnO₃ and RMn₂O₅, a model of the electromagnon response is developed.  This results in the direct excitation of a Brillouin zone boundary magnon by the electric field of the electromagnetic wave, as opposed to the usual magnetic resonance which is the zone center magnon excited by the magnetic field of light. These results demonstrate that the symmetric exchange interaction is responsible for all the observed dynamic magnetoelectric effects, and opens a new avenue for studying multiferroic and frustrated magnets.