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arXiv · 1610.04455

Magnetic resonances of multiferroic TbFe$_3$(BO$_3$)$_4$

Dávid Szaller·Vilmos Kocsis·Sándor Bordács·Titusz Fehér·Toomas Rõõm·Urmas Nagel·Hans Engelkamp·Kenya Ohgushi·István Kézsmarki
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Abstract

Low-energy magnetic excitations of the easy-axis antiferromagnet TbFe$_3$(BO$_3$)$_4$ are investigated by far-infrared absorption and reflection spectroscopy in high magnetic fields up to 30 T. The observed field dependence of the resonance frequencies and the magnetization are reproduced by a mean-field spin model for magnetic fields applied both along and perpendicular to the easy axis. Based on this model we determined the full set of magnetic interactions, including Fe-Fe and Fe-Tb exchange interactions, single-ion anisotropy for Tb ions and $g$-factors, which describe the ground-state spin texture and the low-energy spin excitations of TbFe$_3$(BO$_3$)$_4$. Compared to earlier studies we allow a small canting of the nearly Ising-like Tb moments to achieve a quantitative agreement with the magnetic susceptibility measurements. The additional high energy magnetic resonance lines observed, besides the two resonances expected for a two-sublattice antiferromagnet, suggest a more complex six-sublattice magnetic ground state for TbFe$_3$(BO$_3$)$_4$.

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Dávid Szaller, Vilmos Kocsis, Sándor Bordács, Titusz Fehér, Toomas Rõõm, Urmas Nagel, Hans Engelkamp, Kenya Ohgushi, István Kézsmarki. 2016-10-14. Magnetic resonances of multiferroic TbFe$_3$(BO$_3$)$_4$. https://doi.org/10.1103/physrevb.95.024427

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