THERMODYNAMIC FLUCTUATION ANALYSIS IN TL2BA2CA1-XYXCU2O8-0.25) SYSTEM(Y (Z=0)

We report systematic conductivity fluctuation measurements above the m ean-field transition temperature T-c for T1(2)Ba(2)Ca(1-x)Y(x)Cu(2)O(8 +y) (x = 0-0.25). The excess conductivity has been analysed in terms o f the Aslamazov-Larkin, Lawrence-Doniach (LD) and Maki-Thompson (Mr) m odels. The analysis of the LD fit shows that the system is highly anis otropic and the interlayer coupling J decreases with decrease in the h oles in the system. In the under-doped region the dependence of T-c 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 MI. contribu tion increases with decrease in the interlayer coupling strength.