Effects of CaZrO3 doping on the oxygen vacancy formation and dielectric properties of BaTiO3 ceramics sintered in a reducing atmosphere

Abstract

This study investigates the role of CaZrO₃ doping in suppressing oxygen vacancies and enhancing the dielectric properties of BaTiO₃ ceramics sintered in reducing atmospheres, a critical challenge for base-metal electrode multilayer ceramic capacitors (BME-MLCCs). Advanced characterization techniques, including X-ray photoelectron spectroscopy (XPS) and impedance spectroscopy, reveal that CaZrO₃ doping significantly reduces oxygen vacancy concentrations and Ti³⁺ formation, mitigating defect-induced leakage currents. The optimized doping level (4-mol% CaZrO₃) promotes the formation of a core–shell microstructure, stabilizing the dielectric properties while achieving a high insulation resistivity and maintaining a dielectric constant of ~ 1900. These findings demonstrate that CaZrO₃ not only shifts the Curie temperature but also enhances long-term reliability and operational stability under reducing conditions. This study addresses critical gaps in existing research by providing a comprehensive understanding of defect suppression mechanisms and offering practical solutions for advancing high-reliability BME-MLCCs.