Publication Details
Abstract
High-temperature superconducting samples of HgBa2Ca2Cu3O8+δ (Hg-1223) were synthesized via the solid-state reaction method and sintered at 800°C, 825°C, and 850°C to investigate the effect of sintering temperature on structural, microstructural, and superconducting properties. X-ray diffraction (XRD) analysis confirmed the formation of the Hg-1223 phase in all samples, with varying phase purity and lattice parameters. The sample sintered at 800°C showed the presence of secondary phases and incomplete crystallization, while higher temperatures improved crystallinity but introduced minor secondary phases. Scanning electron microscopy (SEM) at 5 μm magnification revealed progressive grain growth, enhanced connectivity, and reduced porosity with increasing sintering temperature, with the 850°C sample exhibiting the most compact and homogeneous microstructure. Electrical resistivity measurements demonstrated superconducting transitions with Tc(onset) ranging from 140.6 K to 149.7 K and Tc(offset) from 120 K to 129 K, with the transition width (ΔTc) narrowing at intermediate temperatures, reflecting improved structural homogeneity and intergranular connectivity. The energy gap values remained approximately constant (~0.026–0.034 eV), confirming the presence of the superconducting phase. Overall, the solid-state reaction method effectively produces Hg-1223 superconductors, with the 850°C sample providing the optimal balance of phase formation, microstructural quality, and superconducting performance, suggesting its suitability for future high-temperature superconducting applications.