Terahertz spectroscopy of electromagnons in Eu_{1-x}Y_xMnO_3

TL;DR

This study investigates the terahertz dielectric spectra of yttrium-doped EuMnO3, revealing electromagnons and magnetoelectric effects that vary with doping and magnetic field, advancing understanding of multiferroic properties.

Contribution

It provides the first detailed terahertz spectroscopic analysis of electromagnons in Eu_{1-x}Y_xMnO_3 across different doping levels, highlighting doping-dependent electromagnon behavior.

Findings

Electromagnons appear for x >= 0.2 near 20 cm^{-1}

Doping increases the dielectric strength of electromagnons

External magnetic fields can suppress electromagnons in Eu_{0.8}Y_{0.2}MnO_3

Abstract

Dielectric permittivity spectra of yttrium-doped EuMnO$_3$ in the composition range 0 =< x =< 0.5 have been investigated in the terahertz frequency range. Magnetoelectric contributions to the permittivity were observed in all compositions for ac electric fields parallel to the crystallographic a-axis. Well defined electromagnons exist for x >= 0.2 close to \nu ~ 20 cm^{-1} and with dielectric strength strongly increasing on doping. In addition to electromagnons, a broad contribution of magnetoelectric origin is observed for all compositions. For Eu_{0.8}Y_{0.2}MnO_3 the electromagnons can be suppressed by external magnetic fields which induce a canted antiferromagnetic phase. Magnetoelectric effects in the different doping regimes are discussed in detail.