Abstract
A series of superconducting samples of type Tl0.8Hg0.2Ba2Ca2-xRxCu3O9-delta, where R = Sm and Yb with 0 <= x <= 0.15, were prepared in a sealed quartz tube via a solid-state reaction technique. The electrical resistivity p(T) was measured as a function Of temperature using the conventional dc four-probe technique. The fluctuation conductivity Delta sigma, above the superconducting transition temperature T sigma was analyzed as a function of temperature using the Aslamazov and Larkin model. It exhibits five different fluctuation regions namely critical (cr), three-dimensional (3D), two-dimensional (2D), one-dimensional (1D) and short-wave, (sw). The zero-temperature coherence length, the effective layer thickness of the two dimensional system, the wire cross-sectional area for one dimensional systems and the interlayer coupling strength were estimated as a function of the substitution-content x. Furthermore, the thermodynamics critical field, lower critical magnetic field, upper critical magnetic field, critical current density and Fermi energy are Calculated from the Ginzburg number. (C) 2008 Elsevier Ltd. All rights reserved.