Abstract
The main role played by mobile carriers and fluctuation induced conductivity (FIC) in (Cu0.5Tl0.5-x K (x) )Ba2Ca3Cu1Zn3O12-delta (x=0, 0.25) superconductor samples are analyzed in the light of the Aslamazov-Larken (AL) theory. The enhancement of three-dimensional (3D) conductivity and grain size is achieved with K-doping at Tl sites in the (Cu0.5Tl0.5-x K (x) )Ba2O4-delta charge reservoir layer, which are further improved by post-annealing the samples in oxygen. The improvement of these factors causes the increase in cross-over temperature (T (o)), zero resistivity critical temperature {T (c)(R=0)} and T (c)(onset) of diamagnetism to their higher values. We have also evaluated the exponents (lambda (2D) and lambda (3D)), zero temperature coherence lengths xi (c)(0), and interlayer coupling (J) for these samples and tried to correlate them to the superconductivity order parameters.