Evolution of basic features of Bi1.8Pb0.4Sr2Ca2.2Cu3Oy ceramic systems with NiO impurity

In the current work, we have investigated the role of different nickel oxide (NiO)(x) impurity addition levels (0 & LE; x & LE; 1.2) on the fundamental crystallographic, morphological, electrical, magnetic, critical current density, and superconducting features of Bi1.8Pb0.4Sr2Ca2.2Cu3Oy (Bi-2223) by the temperature-dependent electrical resistivities (& rho;-T), X-ray diffraction data (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and magnetic hysteresis (M-H) measurements for the first time. The NiO-added Bi-2223 ceramics have been produced by the standard solid-state reaction method at 840 & DEG;C for 36 h in the air atmospheric conditions. EDX investigations have demonstrated that there appear no extra contamination and additional phases for any anionic or cation-including phases. Besides, the Ni impurity concentration has been observed to increase systematically depending on the impurity amount. Thus, the NiO impurities have been added to the ceramic matrix as requested. Similar findings have been confirmed by the XRD examinations. The experimental results have pointed out the multiple substitution reaction of Ni-sites with the Bi-sites, Ca-sites, and Cu-sites in the Bi-2223 system. Moreover, the experimental results have shown that all the fundamental features are strongly dependent upon the NiO addition level due to the variation of Cu-O-2 interlayer bonding forces, grain alignment distributions, mobile carrier concentrations in the in-plane Cu-O-2 layer x(2)-y(2) bands, and coupling probabilities between the adjacent layers in the crystal structure. Similarly, the induction of new impurity phase formations, grain boundaries, modulation of Bi-O double layers, spin fluctuations, inhomogeneities, structural defects, and non-recoverable structural problems have also triggered the decrease in the main characteristic quantities. On this basis, the microstructural morphology and related crystallographic features have been noted to degrade with the impurity. Furthermore, the presence of NiO impurity has resulted in a decrement in the flux-pinning centers due to the increase in the lower resistance regions against the flux drifts in the bulk crystal system. All in all, the addition of NiO impurity in the Bi-2223 ceramic matrix is not a good idea for the improvement in the fundamental features of the Bi-2223 superconducting structure.