The 63Cu and 17O NMR studies of spin susceptibility in differently doped Tl2Ba2CaCu2O8−δ compounds

Abstract The NMR line shifts, spin–lattice relaxation rate T 1 −1 of 63 Cu and 17 O and 63 Cu spin–spin relaxation rate 63 T 2 −1 were measured in normal and superconducting states of the magnetically oriented ceramics of Tl 2 Ba 2 CaCu 2 O 8− δ with different hole concentrations ( T c =102 K, T c =112 K, T c =104 K) involving the optimally doped composition ( T c =112 K). The magnetic hyperfine fields on the Cu and O atoms in the CuO 2 layer were estimated using the temperature dependences of the Knight shift. The temperature dependences of magnetic correlation length ξ and characteristic energy Γ Q of antiferromagnetic (AF) spin fluctuations were analyzed using the 63,17 T 1 −1 and 63 T 2 −1 data obtained. In going to overdoped state of cuprate the crossover in temperature between different regimes of spin fluctuations is discussed taking into account the magnetic phase diagram proposed for superconducting cuprates by Barzykin and Pines [V. Barzykin, D. Pines, Phys. Rev. B 52 (1995) 13585].