Theory of nuclear spin-spin coupling in YBa₂Cu₃O7-δ

The indirect nuclear spin-spin coupling between Cu nuclei in the CuO₂ planes of YBa₂{Cu}₃O_7-δ, deduced from ⁶³Cu transverse relaxation, is shown to yield information about the wave-vector dependence of the real part of the planar Cu static electron-spin susceptibility. The coupling is evaluated with no adjustable parameters using the antiferromagnetic Fermi-liquid theory of Millis, Monien, and Pines, providing a new test of that model. At 100 K, the theoretical relaxation time is 190±{}75 {μ}sec versus the experimental 130±{}10 {μ}sec.