Calcium copper titanate

Calcium copper titanate (CCTO), with the chemical formula CaCu3Ti4O12, is an inorganic compound known for its exceptionally high dielectric constant of over 10,000 at room temperature. It was first synthesized in 1967 but gained attention only after Mas Subramanian and his team at DuPont discovered its remarkable dielectric properties in 2000. The material is derived from a cubic perovskite structure with octahedral tilting distortions, leading to unique structural features. Its synthesis typically involves high-temperature solid-state reactions using metal carbonates and oxides.

CCTO's dielectric constant far exceeds theoretical predictions based on intrinsic properties, suggesting its high permittivity arises from grain boundary effects rather than crystal structure alone. This phenomenon is attributed to an internal barrier layer capacitance (IBLC) formed during processing, which achieves effective permittivity values over 10,000. Unlike other materials like BaTiO3, CCTO can be fabricated in a single step, making it a promising alternative for capacitor applications.

Despite its advantages, the exact origin of its dielectric behavior remains debated due to discrepancies between observed and calculated values. Its unique properties make it valuable for use in capacitors and other electronic applications, though further research is needed to fully understand its mechanism.