%0 Journal Article
%T Spin Diffusion in the S=1/2 Quasi One-Dimensional Antiferromagnet ¦Á-VO(PO_3)_2 via 31P NMR
%A Jun Kikuchi
%A Naohiko Kurata
%A Kiyoichiro Motoya
%A Touru Yamauchi
%A Yutaka Ueda
%J Physics
%D 2001
%I arXiv
%R 10.1143/JPSJ.70.2765
%X Low-frequency spin dynamics in the S=1/2 antiferromagnetic spin-chain compound \alpha-VO(PO_3)_2 has been studied by means of 31P NMR. The nuclear spin-lattice relaxation rate 1/T_1 at the P site exhibits H^{-1/2} dependence on the applied magnetic field (H) at temperatures (T) well above the intrachain coupling strength J/k_{B} = 3.50 K indicating one-dimensional diffusive spin dynamics. The diffusive contribution to 1/T_1 decreases on cooling as electronic spins acquire short-range antiferromagnetic correlations within the chain, and vanishes almost entirely around T \approx J/k_{B}. This is accompanied by an apparent increase of the spin-diffusion constant from the value expected in the classical limit. On the other hand, the field-independent part of 1/T_1 increases with decreasing temperature, which may be a precursor for the true long-range antiferromagnetic ordering found below T_{N} = 1.93 \pm 0.01 K.
%U http://arxiv.org/abs/cond-mat/0102365v2