Colossal permittivity in titanium dioxide ceramics modified by tantalum and trivalent elements

Abstract Colossal permittivity (CP) materials continue to attract significant interest for their applications in high-performance capacitors and scaling advances in electronic devices. However, the unbalanced developments of their dielectric constants, dielectric losses, and stabilities still hinder practical applications. In this study, we attained a colossal permittivity (er = 104∼105, 1 kHz) in a series of new titanium dioxide (i.e., (A0.5Ta0.5)xTi1−xO2, where A = Al, Sm, Bi, Fe, In, Dy, Ga, Gd, Yb, or Sc) ceramics containing Ta and trivalent elements that is comparable or superior to the previously reported results in In and Nb co-doped ceramics. In addition, a low dielectric loss (tan δ∼5.4%, 1 kHz) was achieved in the ceramics by tailoring the types of trivalent elements used; such a ceramic also shows relatively good dielectric properties with regard to frequency (102∼106 Hz) and temperature (−150–200 °C) stabilities. The formation of defect-dipole clusters (e.g., Al 3 + V O · · Ti 3 + and Ta 5 + Ti 3 + A Ti (A = Ti3+/Al3+/Ti4+)) induced by Ta and trivalent elements should be responsible for the observed enhancements in dielectric properties. We believe that TiO2-based ceramics are one of the most promising candidates in the field of electronic and energy-storage devices.