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 \(T_{c}^{offset}\) $T_c^{\mathit{offset}}$ and \(T_{c}^{onset}\) $T_c^{\mathit{onset}}$ , 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.