Tl, Cu-NMR study on high-Tc cuprate TlBa2Y1-xCaxCu2O7

Tl, Cu-NMR study has been performed on the high-Tc cuprate, TlBa2Y1-xCaxCu2O7 with wide range hole concentration from the antiferromagnetic (x=0) to the slightly overdoped (x = 1.0). For superconducting samples (x = 0.6-1.0) the local spin susceptibility (KS) at Cu-site stayed constant around room temperature, and starts slight a decrease from 160 K, which is higher than Tc. This T-dependence is what has been reported in other high-Tc cuprates in overdoped region. (T1T)-1 at Tl-site for every superconducting sample, which obeys Curie-Weiss law at high temperature, showed a significant reduction from TSG (>Tc), suggesting the existence of spin-gap even in slightly overdoped region