Origin of electromagnon excitations in \textit{R}MnO$_3$

TL;DR

This paper explains the origin of electromagnon excitations in extit{R}MnO$_3$ manganites through Heisenberg spin coupling, linking dynamic and static magnetoelectric effects confirmed by experimental data.

Contribution

It introduces a model that attributes electromagnon excitations primarily to Heisenberg interactions, contrasting with the weaker Dzyaloshinskii-Moriya contribution, and connects dynamic and static magnetoelectric phenomena.

Findings

Electromagnons are explained by Heisenberg coupling.

Experimental data supports the model across temperature and magnetic field.

A connection between spiral phase dynamics and static magnetoelectric coupling is established.

Abstract

The origin of electromagnon excitations in cycloidal \textit{R}MnO$_3$ is explained in terms of the Heisenberg coupling between spins despite the fact that the static polarization arises from the much weaker Dzyaloshinskii-Moriya (DM) exchange interaction. We present a model that incorporates structural characteristics of this family of manganites that is confirmed by far infrared transmission data as a function of temperature and magnetic field and inelastic neutron scattering results. A deep connection is found between the magnetoelectric dynamics of the spiral phase and the static magnetoelectric coupling in the collinear E-phase of this family of manganites.