Fluctuation conductivity in (Bi,Pb)2Sr2Ca2Cu3Oy/Ag multi-layered bulk system

Fluctuation conductivity sigma' perpendicular to the layer surface is studied in (Bi,Pb)(2)Sr(2)Ca(2)Cu(3)Ogamma/Ag multi-layered (Bi/Ag) systems prepared by stacking Ag sheets alternatively into the oxide superconductors. It has already been known that the critical current density J(c) in the layered systems is enhanced in proportion to the number of Ag sheets. Experimental data on sigma' are analyzed in terms of the Lawrence-Doniach theory with momentum- and energy-cutoffs. Because of good agreement between theory and experiment, we can evaluate several fitting parameters, and discuss relationship among the parameters and J(c). The results for our study could show an enhanced anisotropic character of the Bi/Ag systems probably due to the formation of a highly oriented structure, resulting in the improvement of J(c). (C) 2004 Elsevier B.V. All rights reserved.