Crystal chemistry, dielectric and thermoelectric properties of CaTiO3-based ceramics. A review

Ceramics with perovskite structure, featuring high dielectric constant, low losses, minimal remanent polarization, and high dielectric strength, are essential for multilayer ceramic capacitors in electronics, hybrid and electric vehicles, and dielectric resonators for microwave and RF systems. Calcium titanate (CaTiO₃), though less studied, offers some key advantages over lead-free ferroelectric perovskites: no hysteretic losses, wider band gap, enhanced dielectric strength, nearly linear polarization-field response, and superior chemical and thermal stability. Its properties can be widely tailored through formation of solid solutions, leveraging perovskite structural flexibility. Recently, CaTiO₃-based ceramics have also emerged as sustainable thermoelectrics, achieving in a few years performance comparable to best oxide materials. This review highlights the state-of-the-art on CaTiO₃, emphasizing the role of chemical modification, defect chemistry, charge transport, microstructure, and interfaces in optimizing properties.