Effect of Al Substitution on Structural and Electrical Properties of Bi1.6Pb0.4Sr2CaCu2−xMxO8+δ Superconducting Ceramics
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Date
2012
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Journal ISSN
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Publisher
Springer
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, Bi–Pb–Sr–Ca–Cu–O system, Substitution, Normal state