We studied magnetic excitations in a low-temperature ferroelectric phase of
the multiferroic YMn2O5 using inelastic neutron scattering (INS). We identify
low-energy magnon modes and establish a correspondence between the magnon peaks
observed by INS and electromagnon peaks observed in optical absorption [1].
Furthermore, we explain the microscopic mechanism, which results in the
lowest-energy electromagnon peak, by comparing the inelastic neutron spectral
weight with the polarization in the commensurate ferroelectric phase.Comment: 4 pages, 4 figure