Synthesis and Characterization of Eu-Substituted Bismuth-Based Superconductors via Chemical Sol-Gel Method

The study seeks to investigate the role of Eu substitution in improving the characteristics of bismuth-based superconductors, employing the sol-gel technique as a flexible synthesis methodology. The study is focused on superconductor samples of the composition Bi1.7-xPb0.3EuxSr1.9Ba0.1Ca2Cu3O10+δ, where x ranged from 0.0 to 0.5 through systematic investigation where the Pb and Ba are maintained at fixed values 0.3 and 0.1 respectively. The influence of partially substituting Eu for Bi on superconducting characteristics was thoroughly explored. Electrical resistivity measurements unveiled a notable enhancement in critical temperature (Tc) with the incorporation of Eu, peaking at x = 0.2 with a Tc of 114 K. X-ray diffraction (XRD) analysis demonstrated an orthorhombic structure, primarily comprising the high-Tc phase (2223), which exhibited a substantially higher ratio compared to the low phase (2212) within the same sample. Field emission scanning electron microscopy (FE-SEM) unveiled plate-like nanostructures, with discernible variations in morphology corresponding to varying levels of Eu content. The oxygen content (δ) was meticulously calculated for all prepared samples, showcasing consistency with the critical temperature values increasing proportionally with the concentration of Eu in the compound. The highest δ value, reaching 0.320, was observed at x = 0.2, aligning with the peak Tc value. The study elucidated the intricate relationship between Eu doping, structural configuration, and superconducting properties in BSCCO materials. These findings not only deepen our understanding of the underlying mechanisms governing superconductivity in complex oxide systems but also offer valuable insights for optimizing of superconducting materials for practical applications.