ANALYSIS OF NUCLEAR-RELAXATION EXPERIMENTS IN HIGH-TC OXIDES BASED ON MILA-RICE HAMILTONIAN

Nuclear relaxation experiments of 63Cu, 17O and 89Y NQR/NMR in high Tc 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/T1), 89(1/T1) and the approximate T-linear behavior of 63(1/T1) at higher temperatures can be associated with the same d-spin fluctuations around q~0. The anisotropy data of 63(1/T1) were also explained consistently, from which the values of hyperfine coupling constants were determined. The contribution of antiferromagnetic d-spin fluctuations to 63(1/T1) was extracted from raw data without any adjustable parameters. The saturated value of it above ~150K 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. © 1990, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.