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arXiv · 1008.4709

Electromagnons in the spin collinear state of a triangular lattice antiferromagnet

S. Seki·N. Kida·S. Kumakura·R. Shimano·Y. Tokura
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Abstract

Terahertz time-domain spectroscopy was performed to directly probe the low-energy (1-5 meV) electrodynamics of triangular lattice antiferromagnets CuFe1-xGaxO2 (x = 0.00, 0.01, and 0.035). We discovered an electromagnon (electric-field-active magnon) excitation at 2.3 meV in the paraelectric up-up-down-down collinear magnetic phase, while this electromagnon vanishes in the ferroelectric helimagnetic phase. Anti-correlation with noncollinear magnetism excludes the exchange-striction mechanism as the origin of dynamical magnetoelectric coupling, and hence evidences the observation of spin-orbit coupling mediated electromagnon in the present compound.

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S. Seki, N. Kida, S. Kumakura, R. Shimano, Y. Tokura. 2010-08-27. Electromagnons in the spin collinear state of a triangular lattice antiferromagnet. https://doi.org/10.1103/physrevlett.105.097207

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