Effect of oxygen-doping on Bi2Sr2Ca2Cu3O10+δ vortex matter:: Crossover from electromagnetic to Josephson interlayer coupling

We study the effect of oxygen-doping on the critical temperature T,, the vortex matter phase diagram, and the nature of the coupling mechanism between the Cu-O layers in the three-layer Bi(2)Sr(2)Ca(2)Cu(3)O(10+delta) (Bi-2223) compound. Contrary to previous reports, in the overdoped (OD) regime, we do find a variation in T(c) by increasing the oxygen partial pressure of the postannealing treatment. This variation is less significant than in the bilayer compound Bi(2)Sr(2)CaCu(2)O(10+delta) (Bi-2212) and does not follow the universal T(c) vs delta relation. Magnetic measurements reveal that increasing delta enlarges the field and temperature stability of the Bragg glass phase. These findings imply that the interlayer coupling between Cu-O layers enhances with delta. The anisotropy parameter estimated from directional first-penetration field measurements monotonously decreases from 50 in the underdoped (UD) to 15 in the OD regimes. However, the in-plane penetration depth presents a boomerang-type behavior with delta, reaching its minimum value close to optimal doping. These two facts lead to a crossover from a Josephson OD to electromagnetic UD-dominated coupling of adjacent Cu-O layers in the vicinity of optimal doping.