Abstract:
The changes in phase evolution, structural, superconducting and flux pinning properties of (Bi, Pb)-2212 superconductor due to the addition of the rare earth Dy have been studied. Bulk polycrystalline samples were used for the study in which Dy content was varied from x = 0.0 to 0.5 on a general stoichiometry of Bi1.7Pb0.4Sr2Ca1.1Cu2.1DyxOy. It was found that the Dy atoms enter into the structure, replacing Sr and Ca with significant changes in the lattice parameters, microstructure, hole concentration, normal state resistivity and flux pinning strength of the system. Consequently, the critical temperature (TC), critical current density (JC) and the field dependence of JC (JC–B characteristics) of the Dy added samples were found to be enhanced considerably for optimum doping levels. A maximum TC−onset of 93.4 K (for x = 0.4) and a maximum JC of 692 A cm−2 at 64 K (for x = 0.2) were observed for doped samples, as against 75.8 K and 107 A cm−2, respectively, for the pure sample. The enhancement in the superconducting properties, particularly in the JC–B characteristics, due to Dy addition seems to have great technological significance.
