We present a study on the correlation of the superconducting critical temperature (Tc) and structural morphology with a chemically substituted high-temperature superconductor (HTS) (Bi,Pb)-2212 via Powder X-ray Diffraction (PXRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), and d c magnetometry. The elements Zn, Y, Ti, and Nd are incorporated within the bismuth cuprate structure at amounts that extend the ranges currently found in literature.

High-temperature superconductors with a nominal composition Bi2Pb0.3Sr2Ca2Cu3-xCoxO10+δ for (0≤x≤3) were prepared by solid-state reaction method. Effects of the Co substitution on Cu sites have been investigated to obtain the optimum concentration for the formation and stabilization of the superconducting samples. The results of electrical resistivity measurements of the samples showed that increasing x substituting Co enhance the superconducting properties except for the samples with x=3 yield semiconductor behavior. The higher critical temperature TC found at 118 K, which is for the composition Bi2Pb0.3Sr2Ca2Cu2.2Co0.8O0+δ, which has the highest value of excess oxygen content 0.315. The X-ray diffraction analysis for all superconducting samples showed an orthorhombic structure with two phases, high-Tc 2223 phase and low-TC 2212 phase. X-ray spectroscopy analysis showed that the compositions with x=0.6 and 0.8 samples did not contaminate during the synthesis processes. The scanning electron microscope has been used to identify the morphology of the superconducting phase. The plate-like grains of the high Bi- 2223 phase appeared in most micrographs of the superconducting samples besides changes morphology of samples with increasing dopant concentration.

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High-temperature superconductors with a nominal composition Bi2- xZrxPb0.4Sr2Ca2Cu3Oy for (0≤x≤0.3) were prepared by solid-state reaction method. Effects of the Zr nanoparticles substitution at Bi sites have been studied to obtain the optimum concentration for the formation and stabilization of the superconducting samples. Electrical resistivity measurements of the samples showed that the higher critical temperature TC was found at 118 K, which is for the composition Bi1.95Zr0.05Pb0.4Sr2Ca2Cu3Oy. Semiconductor behavior noticed for samples with concentration higher than 0.2. The X-ray diffraction results for all superconducting samples showed an orthorhombic structure with two phases, 2223 high-TC phase and 2212 low-TC phase. The scanning electron microscope has been used to identify the morphology of the superconducting phase. The plate-like grains of the high Bi-2223 phase appeared in most samples besides changes in morphology of the samples with increasing dopant concentration

Bi2Pb0.3Sr2Ca2Cu3-xCoxO10+δ high temperature superconductors with x=0, 0.2 and 0.4 were prepared by a solid state reaction method. The samples properties have been investigated structurally by X-ray diffraction and morphologically by scanning electron microscopy. Structural analysis showed that two superconducting phases coexist in the samples high temperature Bi-2223 and low-temperature phase 2212 with orthorhombic structure for all samples. Four point probe method was used to study the electrical properties of the samples and all of them showed superconductivity behavior. The transition temperature increases with the increasing Co concentration and sintering temperature. Bi2Pb0.3Sr2Ca2Cu3-xCoxO10+δ superconductor sintered at 130 0C shows highest critical temperature 114 K.