[Zurück]

N. Büttgen, H.A. Krug von Nidda, L. Svistov, L. Prozorova, A. Prokofiev, W. Assmus:
"Spin-modulated quasi-one-dimensional antiferromagnet LiCuVO₄";
Physical Review B, 76 (2007), S. 014440-1 - 014440-11.

Spin-modulated quasi-one-dimensional antiferromagnet LiCuVO₄

N. Büttgen and H.-A. Krug von Nidda
Center for Electronic Correlations and Magnetism EKM, Experimentalphysik V, Universität Augsburg, D-86135 Augsburg, Germany

L. E. Svistov and L. A. Prozorova
P.L. Kapitza Institute for Physical Problems, RAS, 119334 Moscow, Russia

A. Prokofiev and W. Aßmus
Physikalisches Institut, Johann-Wolfgang-Goethe-Universität, D-60054 Frankfurt, Germany

We report on magnetic resonance studies within the magnetically ordered phase of the quasi-one-dimensional antiferromagnet LiCuVO₄. Our studies reveal a spin reorientational transition at a magnetic field H_c1~25 kOe applied within the crystallographic ab plane in addition to the recently observed one at H_c2~75 kOe [M. G. Banks et al., J.Phys.: Condens.Matter 19, 145227 (2007)] Spectra of the antiferromagnetic resonance along low-frequency branches can be described in the framework of a macroscopic theory of exchange-rigid planar magnetic structures. These data allow us to obtain the parameter of the anisotropy of the exchange susceptibility together with a constant of the uniaxial anisotropy. Spectra of ⁷Li nuclear magnetic resonance (NMR) show that, within the magnetically ordered phase of LiCuVO₄ 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 Gibson et al. [Physica B 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.

http://dx.doi.org/10.1103/PhysRevB.76.014440

http://dx.doi.org/10.1103/PhysRevB.76.014440