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Spin-modulated quasi-1D antiferromagnet LiCuVO_4

N. Buettgen·H. -A. Krug von Nidda·L. E. Svistov·L. A. Prozorova·A. Prokofiev·W. Assmus
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Abstract

We report on magnetic resonance studies within the magnetically ordered phase of the quasi-1D antiferromagnet LiCuVO_4. Our studies reveal a spin reorientational transition at a magnetic field H_c1 ~ 25 kOe applied within the crystallographical (ab)-plane in addition to the recently observed one at H_c2 \~75 kOe [ M.G. Banks et al., cond-mat/0608554 (2006)]. Spectra of the antiferromagnetic resonance (AFMR) along low-frequency branches can be described in the frame of a macroscopic theory of exchange-rigid planar magnetic structures. These data allow to obtain the anisotropy of the exchange interaction together with a constant of the uniaxial anisotropy. Spectra of 7Li nuclear magnetic resonance (NMR) show that, within the magnetically ordered phase of LiCuVO_4 in the low-field range H < H_c1, a planar spiral spin structure is realized with the spins lying in the (ab)-plane in agreement with neutron scattering studies of B.J. Gibson et al. [Physica B Vol. 350, 253 (2004)]. Based on NMR spectra simulations, the transition at H_c1 can well be described as a spin-flop transition, where the spin plane of the magnetically ordered structure rotates to be perpendicular to the direction of the applied magnetic field. For H > H_c2 ~ 75 kOe, our NMR spectra simulations show that the magnetically ordered structure exhibits a modulation of the spin projections along the direction of the applied magnetic field H.

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N. Buettgen, H. -A. Krug von Nidda, L. E. Svistov, L. A. Prozorova, A. Prokofiev, W. Assmus. 2007-01-04. Spin-modulated quasi-1D antiferromagnet LiCuVO_4. https://doi.org/10.1103/physrevb.76.014440

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