Effect of Ba and Mg Substitution on the Phase Formations of Combustion Synthesized BSCCO Superconductor

BSCCO (Bi-Sr-Ca-Cu-Oxide) high-temperature superconductor has a nominal composition of Bi₂Sr₂CaCu₂O₈ and Bi₂Sr₂Ca₂Cu₃O₁₀. The main objective of this research is to produce a high-temperature superconducting BSCCO with barium and magnesium substitutions in a single step and to study the effect of substitution on the formation of superconducting Bi-2212 and Bi-2223 phases. BSCCO high-temperature superconductor has a nominal composition of Ba_xMg_yBiSr₂Ca₂Cu₃O₁₀ (x, y = 1,0; 0,1; 0.5,0.5) which is synthesized using combustion synthesis with an ignition temperature of 500°C for one hour. The synthesized powders were characterized using X-ray diffraction, scanning electron microscopy–energy dispersive spectroscopy, and differential scanning calorimetry–thermogravimetric analysis to determine the phases present and the particles morphology. SEM analysis reveals the presence of powder agglomerates consisting of ultra-fine particles of 170 nm to 1347 nm size range, which significantly affects superconductivity. EDS analysis of the powders confirms the presence of stoichiometric amounts of elements in the BSCCO powder. XRD analysis confirms the presence of two superconducting phases Bi-2212 and Bi-2223, in which Ba-substituted BSCCO shows the highest phase fraction of 19% and 8.5%, respectively. DSC-TGA results showed that there is an initial mass change of up to 7.27% and entropy change from 400 to 1000°C due to crystallization and order of the compound to transform into a highly superconducting material.