Characteristics of the Spin Fluctuation in Tl2Ba2Ca2Cu3O10

We report a 63 Cu and 17 O NMR study in the high- T c superconductor Tl 2 Ba 2 Ca 2 Cu 3 O 10 with T c (max)=127 K. The results of T 1 and T 2 G reveal that the characteristic energy of the antiferromagnetic spin fluctuation Γ Q is higher than that in YBa 2 Cu 3 O 7 , while the magnetic correlation lengths ξ do not differ much from each other. The high T c in this compound is thus related to large Γ Q , suggesting that the superconductivity is spin fluctuation mediated.