Defect structure design of TiO2 ceramics with colossal permittivity by doping with Ti metal powder

Abstract

The miniaturization of electronic components requires materials with colossal permittivity. In this work, titanium-powder-doped TiO2 ceramics with colossal permittivity and a low dielectric loss over a wide range of frequency and temperature were successfully prepared using a solid-state reaction in an Ar atmosphere. TiO2 ceramics with 2% Ti powder doping had the highest permittivity (110,000) and the lowest dielectric loss (0.029) at 1 kHz and room temperature. Systematic defect analysis showed that Ti4+ was successfully reduced to Ti3+ through doping with Ti metal powder. Further, oxygen vacancies were created in the high-temperature inert atmosphere, which promoted the formation of defect clusters with Ti3+−Vo″−Ti3+ as the core. Polarization and local confinement of the defect clusters resulted in the colossal permittivity and low dielectric loss. Therefore, this work provides necessary information and novel ideas for the design of correlated defects in colossal permittivity materials.