Molecular-spin dynamics study of electromagnons in multiferroic RMn$_2$O$_5$

TL;DR

This study uses molecular-spin dynamics simulations to analyze electromagnons in multiferroic RMn$_2$O$_5$, revealing their origins, sensitivities to magnetic wave vectors, and responses to magnetic fields.

Contribution

It provides a detailed simulation-based analysis of electromagnons in RMn$_2$O$_5$, clarifying their origin and behavior under magnetic fields, which was not previously well understood.

Findings

Electromagnon modes are sensitive to magnetic wave vector along the a-axis.

Electromagnon frequencies significantly change under magnetic field.

Static dielectric constant remains relatively unchanged in magnetic field.

Abstract

We investigate the electromagnon in magnetoferroelectrics RMn$_2$O$_5$ using combined molecular-spin dynamics simulations. We identify the origin of the electromagnon modes observed in the optical spectra and reproduce the most salient features of the electromagnon in these compounds. We find that the electromagnon frequencies are very sensitive to the magnetic wave vector along the $a$ direction. We further investigate the electromagnon in magnetic field. Although the modes frequencies change significant under magnetic field, the static dielectric constant electromagnon does not change much in the magnetic field.