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arXiv · 1305.3064

Electromagnon in ferrimagnetic eps-Fe2O3 nanograin ceramics

Christelle Kadlec·Filip Kadlec·Veronica Goian·Marti Gich·Martin Kempa·Stephane Rols·Maxim Savinov·Jan Prokleska·Milan Orlita·Stanislav Kamba
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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.

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Christelle Kadlec, Filip Kadlec, Veronica Goian, Marti Gich, Martin Kempa, Stephane Rols, Maxim Savinov, Jan Prokleska, Milan Orlita, Stanislav Kamba. 2013-08-27. Electromagnon in ferrimagnetic eps-Fe2O3 nanograin ceramics. https://doi.org/10.1103/physrevb.88.104301

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