Thermodynamic fluctuation analysis in Tl2Ba2Ca1-xYxCu2O8+y(x=0-0.25) system

Abstract
We report systematic conductivity fluctuation measurements above the mean-field transition temperature Tc for Tl2Ba2Ca1-xYxCu2O8+y (x=0-0.25). The excess conductivity has been analysed in terms of the Aslamazov-Larkin, Lawrence-Doniach (LD) and Maki-Thompson (MT) models. The analysis of the LD fit shows that the system is highly anisotropic and the interlayer coupling J decreases with decrease in the holes in the system. In the under-doped region the dependence of Tc on J seems to be more comparable with that in the optimally doped region. Incorporating the MT term into the LD model fits our data over quite a high-temperature range. We have also observed that the MT contribution increases with decrease in the interlayer coupling strength.