Abstract
We report electrical conductivity fluctuation analyses on (Bi,Pb)(2)Sr(2)Ca(2)Cu(3)O(x) (denoted as (Bi. Pb)-2223) granular samples added with nano-sized Al(2)O(3) particles. Al(2)O(3) is added to the precursor powders during the final sintering cycle of a multi-step preparation process. Phase analysis by X-ray diffraction (XRD) and granular structure examination by transmission electron microscopy (TEM) were carried out. TEM and energy dispersive X-ray spectroscopy (EDS) analysis have shown nanometric Al-rich phase intergrowth within the (Bi. Pb)-2223 superconducting matrix. The temperature dependence of electrical resistivity as function of magnetic field has been measured on free and 0.2 wt. % Al(2)O(3)-added samples. The effect of microscopic inhomogeneities in the paraconductivity region has been reported. Data about the dimensionality of the thermodynamic fluctuation is obtained by analyzing the excess of conductivity on the basis of the Aslamazov-Larkin theory. Samples show predominately two dimensional (2D) behaviors with cross-over to three dimensional (3D) fluctuations in the mean field region. Magneto-conductivity fluctuation results have shown that the Al-rich phase inclusion in superconducting matrix affects the mean field region of superconducting order parameter of fluctuation.