Overdoping effects in Bi2Sr2CaCu2O8+delta: From electromagnetic to Josephson interlayer coupling - art. no. 172505

We report a study of magnetic, structural, and transport properties of Bi2S r2CaCu2O8+delta single crystals with different degrees of overdoping. The o verdoping is achieved by high oxygen pressure (up to 190 bar) annealing. Th e parameters used to characterize the overdoping were the crystallographic c-axis lattice parameter and the superconducting transition temperature. Th e irreversibility line H-il and the characteristic field of the order-disor der transition of the vortex structure H-sp were obtained from dc magnetiza tion with the applied magnetic held perpendicular to the CuO2 planes. The l arge overdoped range has two well-defined regions: (i) close to the optimal doping the interlayer coupling is mainly electromagnetic and H-sp is given by Phi (0)/lambda (2)(ab) (0) [lambda (ab)(0) is the in-plane penetration depth at T = 0 K], and (ii) with further overdoping the Josephson interlaye r coupling becomes relevant, so H-sp deviates from Phi (0)/lambda (2)(ab) ( 0) and is fixed by the effective-mass anisotropy. All the results indicate an increase in the coupling between CuO2 planes with overdoping.