Magnetic resonance on LiCuVO4

EPR and Li-7 NMR measurements were performed in the distorted inverse spine l V(LiCu)O-4 down to 1.5 K. Anisotropy effects on magnetic resonance spectr a due to the Jahn-Teller distortion of the oxygen octahedra surrounding the copper ions are discussed. The estimation of the spin-spin interactions de duced from the EPR-relaxation rate DeltaH reveals a situation comparable to the prototypical one-dimensional S = 1/2 Heisenberg antiferromagnet CuGeO3 . Approaching three-dimensional antiferromagnetic order (T-N approximate to 2 K) from above, both magnetic relaxation rates, DeltaH(EPR) and (7)(1 /T- 1), respectively, exhibit nearly the same critical divergence reminding to the onset of three-dimensional order in two-dimensional layered systems.