The spin wave excitations of the geometrically frustrated triangular lattice antiferromagnet (TLA) CuFeO2 have been measured using high resolution inelastic neutron scattering. Antiferromagnetic interactions up to third nearest neighbors in the ab plane (J_1, J_2, J_3, with J2/J1≈0.44 and J3/J1≈0.57), as well as out-of-plane coupling (J_z, with Jz/J1≈0.29) are required to describe the spin wave dispersion relations, indicating a three dimensional character of the magnetic interactions. Two energy dips in the spin wave dispersion occur at the incommensurate wavevectors associated with multiferroic phase, and can be interpreted as dynamic precursors to the magnetoelectric behavior in this system.
@article{arxiv.0708.1198,
title = {Magnetic Interaction in the Geometrically Frustrated Triangular Lattice Antiferromagnet $\rm CuFeO_2$},
author = {F. Ye and J. A. Fernandez-Baca and R. S. Fishman and Y. Ren and H. J. Kang and Y. Qiu and T. Kimura},
journal= {arXiv preprint arXiv:0708.1198},
year = {2007}
}