Analysis of Nuclear Relaxation Experiments in HighTcOxides Based on Mila-Rice Hamiltonian

Nuclear relaxation experiments of 63 Cu, 17 O and 89 Y NQR/NMR in high T c oxides have been analyzed within the frame of a phenomenological model proposed by Mila and Rice, supposing that only one spin freedom exists. It was shown quantitatively that 17 (1/ T 1 ), 89 (1/ T 1 ) and the approximate T -linear behavior of 63 (1/ T 1 ) at higher temperatures can be associated with the same d-spin fluctuations around q ∼0. The anisotropy data of 63 (1/ T 1 ) were also explained consistently, from which the values of hyperfine coupling constants were determined. The contribution of antiferromagnetic d-spin fluctuations to 63 (1/ T 1 ) was extracted from raw data without any adjustable parameters . The saturated value of it above ∼150 K is by an order of magnitude lower than that estimated in a localized moment scheme. A possible interplay between magnetism and superconductivity is also discussed.