INFLUENCE OF NANO-AG ADDITION ON PHASE FORMATION AND EXCESS CONDUCTIVITY ANALYSIS OF (CU0.5TL0.5)-1223 SUPERCONDUCTING PHASE

Abstract Ceramic superconducting samples of type (nano-Ag)xCu0.5Tl0.5Ba2Ca2Cu3O10- δ , 0.0 ≤ x ≤ 3.0 wt.%, were successfully synthesized via single step solid-state reaction technique at 850 ºC and under ambient pressure. The samples were characterized by XRD and SEM. Obtained data revealed that the highest grains connectivity volume fraction was detected for the sample with x = 0.15 wt.%. The electrical properties of the prepared samples was examined using the electrical resistivity measurements, and the results proved that the highest superconducting transition temperature Tc was observed at x = 0.15 wt.%. Furthermore, the fluctuation conductivity Δσ (T), above Tc, was analyzed as a function of reduced temperature, t=(T-T_c^mf)/(T_c^mf ), using Aslamazov and Larkin (AL) theory and its modified form given by Lawrence-Doniach (LD) model. Excess conductivity analysis showed crossover between two dimensional (2D) to three-dimensional (3D) with decreasing temperature for all samples. The highest crossover temperature T2D-3D was observed for x = 1.5 wt.%, which showed the smallest coherence length along c-axis ξ (0), Fermi velocity vF, Fermi energy EF and interlayer coupling ν in these samples.