Terahertz spectroscopy of electromagnons in Eu1-xYxMnO3

Dielectric permittivity spectra of yttrium-doped EuMnO3 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 similar to 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 Eu0.8Y0.2MnO3, 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.