Electromagnon in ferrimagnetic eps-Fe2O3 nanograin ceramics

Abstract

Electromagnons are known from multiferroics as spin waves excited by the electric component of electromagnetic radiation. We report the discovery of an excitation in the far-infrared spectra of eps-Fe2O3 which we attribute to an electromagnon appearing below 110 K, where the ferrimagnetic structure becomes incommensurately modulated. Inelastic neutron scattering shows that the electromagnon energy corresponds to that of a magnon from the Brillouin zone boundary. Dielectric measurements did not reveal any sign of ferroelectricity in eps-Fe2O3 down to 10 K, despite its acentric crystal structure. This shows that the activation of an electromagnon requires, in addition to the polar ferrimagnetic structure, a modulation of the magnetic structure. We demonstrate that a combination of inelastic neutron scattering with infrared and / or terahertz spectroscopies allows detecting electromagnons in ceramics, where no crystal-orientation analysis of THz and infrared spectra is possible.

accepted to Phys. Rev. B

References in corpus (13)

• Origin of electromagnon excitations in \textit{R}MnO${}_3$
• Magnetoelectric Coupling in epsilon-Fe2O3
• Theory of electromagnon in the multiferroic Mn perovskites: Vital role of higher harmonic components of the spiral spin order
• Spin wave measurements over the full Brillouin zone of multiferroic BiFeO3
• Colossal magnon-phonon coupling in multiferroic Eu${}_{0.75}$Y${}_{0.25}$MnO${}_3$
• Electromagnons in multiferroic RMn2O5 compounds and their microscopic origin
• Terahertz time-domain spectroscopy of electromagnons in multiferroic perovskite manganites
• Relaxations as key to the magnetocapacitive effects in the perovskite manganites
• Model for twin electromagnons and magnetically induced oscillatory polarization in multiferroic RMnO${}_3$
• Anharmonic Phonons and Magnons in BiFeO3
• Universal exchange-driven phonon splitting in antiferromagnets
• Terahertz and infrared spectroscopic evidence of phonon-paramagnon coupling in hexagonal piezomagnetic YMnO3
• Sinusoidal electromagnon in RMnO3: Indication of anomalous magnetoelectric coupling

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• Possible coupling between magnons and phonons in multiferroic CaMn7O12