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arXiv · 2012.09178

The Magnetoelastic Distortion of Multiferroic BiFeO$_3$ in the Canted Antiferromagnetic State

Toomas Rõõm·Johan Viirok·Laur Peedu·Urmas Nagel·Daniel G. Farkas·David Szaller·Vilmos Kocsis·Sandor Bordács·Istvan Kézsmárki·Dymtro L. Kamenskyi·Hans Engelkamp·Mike Ozerov·Dmitry Smirnov·Jurek Krzystek·Komalavalli Thirunavukkuarasu·Yasuko Ozaki·Yasuhide Tomioka·Toshimitsu Ito·Trinanjan Datta·Randy S. Fishman
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Abstract

Using THz spectroscopy, we show that the spin-wave spectrum of multiferroic BiFeO$_3$ in its high-field canted antiferromagnetic state is well described by a spin model that violates rhombohedral symmetry. We demonstrate that the monoclinic distortion of the canted antiferromagnetic state is induced by the single-ion magnetoelastic coupling between the lattice and the two nearly anti-parallel spins. The revised spin model for BiFeO$_3$ contains two new single-ion anisotropy terms that violate rhombohedral symmetry and depend on the direction of the magnetic field.

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Toomas Rõõm, Johan Viirok, Laur Peedu, Urmas Nagel, Daniel G. Farkas, David Szaller, Vilmos Kocsis, Sandor Bordács, Istvan Kézsmárki, Dymtro L. Kamenskyi, Hans Engelkamp, Mike Ozerov, Dmitry Smirnov, Jurek Krzystek, Komalavalli Thirunavukkuarasu, Yasuko Ozaki, Yasuhide Tomioka, Toshimitsu Ito, Trinanjan Datta, Randy S. Fishman. 2020-12-16. The Magnetoelastic Distortion of Multiferroic BiFeO$_3$ in the Canted Antiferromagnetic State. https://doi.org/10.1103/physrevb.102.214410

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