CU-63,CU-65 INDIRECT SPIN-SPIN COUPLING IN LA1.85SR0.15CUO4

Measurements of the nuclear spin-echo decay time constant T-2G for bot h Cu-63 and Cu-65 in La1.85Sr0.15CuO4 are presented for sample tempera tures ranging from 100 to 300 K. Using methods developed recently, the se measurements are corrected for the effects of T-1 modulation and of spin-spin flip-flop transitions. The results are then compared with p redictions based on Kramers-Kronig integration of recent neutron data, and extrapolations thereof, for chi''((q) over right arrow,omega) Usi ng the foregoing results and calculated corrections for YBa2Cu3O7, we also discuss the evaluation of these systems in terms of quantum disor dered (z=1) vs overdamped (z=2) behavior in the phase diagram proposed by Sokol and Pines.