The effect of PbF2 doping on the structural, electrical and mechanical properties of (Bi,Pb)–2223 superconductor

Abstract

The influence of PbF2 doping on the electrical and mechanical properties of Bi1.8Pb0.4Sr2Ca2.1Cu3.2O10+δ superconducting phase was studied. (PbF2)x Bi1.8Pb0.4Sr2Ca2.1Cu3.2O10+δ samples were prepared by the solid-state reaction method. The PbF2 content 'x' was varied from 0.0 to 0.3 of the sample’s total mass. The characterization of the prepared samples was established by X-ray powder diffraction (XRD), scanning electron microscope (SEM) and Proton Induced Gamma ray Emission (PIGE). Moreover, the electrical resistivity 'ρ(T)' and the transport current density 'J' measurements were carried out via four-probe technique. Phase examination by XRD indicated that the PbF2 doping enhanced the (Bi, Pb) –2223 phase formation up to x = 0.10. On the other hand, the high concentrations of PbF2 retarded the phase formation. Granular investigation, from scanning electron microscope, showed that the grain size was increased as x increased from 0.05 to 0.20 with more grain orientation and inter-coupling between superconducting grains. The results of electrical and mechanical measurements showed that the superconducting transition temperature (Tc), the transport critical current density (Jc) and the Vickers microhardness Hv were found to have optimal value at x = 0.1.