We summarize the existing experimental data on electromagnons in multiferroic RMn2O5 compounds, where R denotes a rare earth ion, Y or Bi, and discuss a realistic microscopic model of these materials based on assumption that the microscopic mechanism of magnetically-induced ferroelectricity and electromagnon absorption relies entirely on the isotropic Heisenberg exchange and magnetostrictive coupling of spins to a polar lattice mode and does not involve relativistic effects. This model explains many magnetic and optical properties of RMn2O5 manganites, such as the spin re-orientation transition, magnetically-induced polarisation, appearance of the electromagnon peak in the non-collinear spin state and the polarisation of light for which this peak is observed. We compare experimental and theoretical results on electromagnons in RMn2O5 and RMnO3 compounds.
@article{arxiv.0806.1207,
title = {Electromagnons in multiferroic RMn2O5 compounds and their microscopic origin},
author = {A. B. Sushkov and M. Mostovoy and R. Valdes Aguilar and S. -W. Cheong and H. D. Drew},
journal= {arXiv preprint arXiv:0806.1207},
year = {2009}
}
Comments
20 pages, 9 figures, to be published in J. Phys.: Condens. Matter, special issue on multiferroics