A high dielectric constant in nano-TiO₂ ceramic prepared by a rapid and high-pressure sintering process

Dense nano-TiO₂ ceramic was prepared by plasma-activated sintering under high pressure. The X-ray photoelectron energy spectrography and X-ray diffraction results revealed the presence of large quantities of oxygen vacancies and Ti³⁺ on the surface and a decrease in the interplanar spacing of rutile (1 1 0), respectively. The extraordinarily high dielectric constant can be attributed to the combination of multiform polarizations, resulting from the intrinsic crystal structure of rutile, and changes in the surface elements' chemical state and crystallographic parameters of the nano-TiO₂ ceramic.