Abstract
Nanometer Al2O3 particles were added to (Bi,Pb)(2)Sr2Ca2Cu3Ox (Bi,Pb)-2223 precursor powders during the final sintering cycle of a multi-step preparation process. The temperature dependence of the resistance in 0 and 0.2% Al2O3-added (Bi,Pb)(2)Sr2Ca2Cu3Ox samples was measured. Data about the dimensionality of the fluctuation is obtained by analyzing the fluctuation conductivity Delta sigma as a function of epsilon=ln(T/T-C) on the basis of the Aslamazov-Larkin theory. Within the mean field region, we first observe a regime dominated by 2D Gaussian fluctuation. With decreasing temperature a crossover occurs at a temperature T-G and the obtained regime was described by critical fluctuations. The Ginzburg number and fluctuation amplitude, increase with addition of nanometer Al2O3 particles. Correlation between fluctuation amplitude and J(C) has been discussed. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.