CU-63 NMR-STUDY OF CONDUCTING DELAFOSSITES

NMR data are presented for the conducting delafossites Y0.99Ca0.01CuO2 .65 and LaCuO2.64. These materials exhibit a planar structure with tri angular arrays of exchange-coupled S = 1/2 (Cu2+) spins. The two compo unds examined show strikingly different quadrupole-broadened NMR powde r patterns, which is evidence for different in-plane arrangements of O 2- ions. Their doped-hole carrier densities are comparable to those of the superconducting cuprates. In consequence, they have Korringa-like T1 processes. We, also find evidence for dynamic Jahn-Teller motion a nd ferromagnetic enhancement of the spin paramagnetism for Y0.99Ca0.01 CuO2.65. T2 studies indicate that the strong antiferromagnetic fluctua tion effects found in the superconducting cuprates are absent.