NMR data are presented for the conducting delafossites Y0.99Ca0.01CuO2.65 and LaCuO2.64. These materials exhibit a planar structure with triangular arrays of exchange-coupled S=1/2(Cu2+) spins. The two compounds examined show strikingly different quadrupole-broadened NMR powder patterns, which is evidence for different in-plane arrangements of O2- 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 and ferromagnetic Benhancement of the spin paramagnetism for Y0.99Ca0.01CuO2.65. T2 studies indicate that the strong antiferromagnetic fluctuation effects found in the superconducting cuprates are absent.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics