Nuclear relaxation in half-integer spin chains at low temperatures (T≪J, the antiferromagnetic exchange constant) is dominated by dissipation from a gas of thermally excited, overdamped, spinons. The universal low-temperature dependence of the relaxation rates 1/${\mathit{T}}_1$ and 1/${\mathit{T}}_{2\mathit{G}}$ is computed.

• Received 20 June 1994

DOI:https://doi.org/10.1103/PhysRevB.50.13006