Novel titanium dioxide ceramics containing bismuth and antimony

Here, we developed one kind of novel TiO2 ceramics with colossal dielectric constant by chemical modifications (Bi3+ and Sb5+), and discussed the physical origin for giant dielectric constant. Effects of Bi and/or Sb on their microstructure, dielectric properties as well as its frequency and temperature stability were studied in detail. It was found that their dielectric properties are strongly sensitive to (Bi,Sb) contents, and colossal dielectric permittivity (CP) (104∼105) together with low dielectric loss (∼5.7%) can be obtained in a wide composition range. In addition, all the ceramics possessed good frequency (102∼106 Hz) and temperature (−150–200 °C) stability of dielectric properties. In addition, the defects caused by the Bi volatilization may be the reason for higher dielectric properties of (Bi0.5Sb0.5)xTi1−xO2 ceramics with respect to (A0.5Sb0.5)xTi1−xO2 (A = In, Pr, Dy, Sm, Gd, Yb, Ga, Al, Fe or Sc). According to the results of complex impedance and XPS, the electron-pinned defect-dipoles may be suitable to explain the CP phenomenon, and oxygen vacancies-induced by Bi3+&Sb5+ substitution for Ti4+ should be responsible for conduction mechanism. We believe that this profound investigation can benefit the development of TiO2 ceramics as a CP material.