TL-205 NUCLEAR-SPIN-LATTICE RELAXATION IN THE ONE LAYER (TL2BA2CUO6), 2 LAYER (TL2CABA2CU2O8) AND 3 LAYER (TL2CA2BA2CUO10) HIGH-TC SUPERCONDUCTORS

We report on the comparison of the 205Tl nuclear spin lattice relaxation rate 1/T1 versus temperature below and above Tc in the three title compounds. Although Tc varies significantly for the three compounds, their relaxation rates 1/T1 behave almost identical above and below Tc. In the regime T > Tc non-Korringa behaviour is observed, resembling the 63Cu relaxation in the CuO2 layer (Cu(2)) of YBa2Cu3O7, whereas for T<Tc the relaxation rate decreases rapidly with decreasing temperature due to a gap opening in the magnetic excitation. However, Korringa behaviour is observed for a Tl defect located between the CuO2 layers in Tl2CaBa2Cu2O8. © 1990.