Improvement in organization of Cu-O coordination and super-electrons in Bi-2212 ceramic matrix with Ag/Sr partial substitution

This study rationalizes the reason for an increase in the electrical conductivity, crystal quality, surface morphology, and superconductive transition temperatures for Bi-2212 superconductors via scientific facts and discussions depending on replacing the optimum Ag/Sr sites in the system for the first time. Every experimental result and related calculations indicate the successful replacement of monovalent Ag+ ions for the divalent Sr2+ ions in the polycrystalline Bi-2212 structure. Moreover, it is observed that the bulk Bi-2212 ceramic prepared with a partial substitution level of x = 0.01 is observed to possess the highest electrical conductivity and superconductive transition temperatures of 84.68 K and 86.26 K for the Tcoffset\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$T_{c}<^>{offset}$$\end{document} and Tconset\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$T_{c}<^>{onset}$$\end{document}, respectively. Besides, in the case of the optimum replacement level, the Bi-2212 ceramic exhibits the most uniform and smoothest surface appearance, highest interactions between the grains, best microcrystal distributions/orientations, and largest average crystalline distribution along the crystal structure. In this regard, this study becomes a leader in broadening the application spectra including the heavy-industrial technologies, innovative, advanced engineering-related sectors, and large-scale application fields for Bi-2212 superconducting ceramics.