NMR measurements were performed on single-crystalline samples of the one-dimensional Heisenberg antiferromagnet (1D HAF) . We investigated and NMR spectra, deduced the respective lineshifts , spin-lattice relaxation rates , and spin-spin relaxation rates and . The results are compared to theoretical predictions for the relaxation rates and deduced from the dynamic susceptibility of a 1D HAF spin chain as proposed by Sachdev [Phys. Rev. B 50, 13006 (1994)]. We document a correspondence between the anisotropic relaxation rates derived from electron paramagnetic resonance linewidth and nuclear magnetic resonance , respectively, the former being well described in the framework of symmetric anisotropic exchange interactions for by Krug von Nidda et al. [Phys. Rev. B 65, 134445 (2002)].
- Received 9 November 2005
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