Effect of Al Substitution on Structural and Electrical Properties of Bi1.6Pb0.4Sr2CaCu2−xMxO8+δ Superconducting Ceramics
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Date
2013
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Springer Science,Business Media New York
Abstract
In this work we study the effect on structural
and electrical properties of superconducting compound
Bi1.6Pb0.4Sr2CaCu2−yMyO8+δ were M = Al (with y =
0–0.6). The samples were prepared by the solid-state reaction
method. The samples have been characterized by X-ray
diffraction (XRD), scanning electron microscopy (SEM),
direct current (DC) resistivity versus temperature ρ(T ) and
alternative current (AC) susceptibility measurements. Structural
analysis shows that the crystalline lattice structure of
the prepared sample belongs, mainly, to the superconduc tive tetragonal phase Bi(Pb)2212. The SEM micrographs
show that in the undoped sample the grain size has a random
distribution with few grains greater than 5 µm. The
grains are very dense and well connected. A quite different
microstructure is obtained for the doped samples of which
grains are more connected with a flat characteristic shape of
Bi(Pb)2212 superconductors. All samples exhibit a superconducting
character and Tc and the superconducting volume
fraction decrease with increasing rate of aluminum.
Description
Keywords
Superconductivity, Substitution, Doping, Resistivity