Dy-modified barium calcium titanate sintered in a reducing atmosphere: Crystal structure, microstructure, and electrical characteristics

The microstructure, crystal structure, and electrical properties of calcium-doped BaTiO3 (BCT) sintered at 1180 °C for 1 h in a reducing atmosphere were investigated in this study. A detailed mechanism for improving the reliability of Dy-modified BCT sintered in a reducing atmosphere has been proposed. Ca in BCT mostly substituted for Ba and occupied A-site, according to the Rietveld analysis. The Dy3+-added sample revealed a core-shell structure with lamellar domain walls in the core region, as seen in TEM images. Curie temperature and dielectric constant increased as calcium concentration increased. Dy3+ doped samples had a higher Curie temperature and dielectric constant than non-doped samples. The Dy-doping and substitution of Ca2+ for Ba2+ can significantly increase the grain conductivity activation energy for Dy-doped BCT sintered under reduction atmosphere. It suggests that Dy3+ and Ca2+ doping can effectively suppress the formation of oxygen vacancies and inhibit their movement, potentially improving the HALT of BME-MLCC.