Thermopower and irreversibility field study of Bi2-xPbxSr2Ca2Cu3O10+y

We have used thermopower and magnetic irreversibility field measurements to probe the triple layer Bi2-xPbxSr2Ca2Cu3O10+y high-temperature superconduc ting cuprate. We find that the thermopower data can be analyzed in terms of a hole concentration deficit on the inner CuO2 plane of delta p similar to 0.05 when the outer CuO2 planes are underdoped. However, this deficit does not appear to affect the magnetic irreversibility field H-irr and it appea rs to be removed once the outer planes are optimally doped. We find that H- irr scales to a universal function, within the accessible hole concentratio n range, and that the maximum irreversitsility field occurs at hole concent rations greater than those that can be achieved in this superconductor. We provide a simple model to account for the hole concentration dependence of the H-irr scaling prefactor in Bi2-xPbxSr2Ca2Cu3O10+y as well as in Bi2Sr2C aCu2O8+y and YBa2Cu3O7-y.