Evidence of finite-size effects in an S=1/2 Heisenberg linear chain LiV2O5 studied by 51V NMR

Nuclear magnetic resonance (NMR) spectra of V-51 nuclei were measured in S = 1/2 Heisenberg linear chains, LiV2O5 and LixV2O5 (x = 0.98 and 0.95). Broad double-peak structure was observed for the pure LiV2O5 and the linewidth increased with the decrease in temperature and the increase in field. The increase of the linewidth became prominent for Li-deficient samples. These experimental facts prove that the staggered moments are induced in a whole system due to the existence of open ends in the chains. The NMR spectra for 2% and 5% Li-deficient samples were interpreted by considering the correlation length of finite-size chains with odd and even number spins. [S0163-1829(98)03142-7].