Origins of Giant Dielectric Properties with Low Loss Tangent in Rutile (Mg1/3Ta2/3)0.01Ti0.99O2 Ceramic

The Mg2+/Ta5+ codoped rutile TiO2 ceramic with a nominal composition (Mg1/3Ta2/3)(0.01)Ti0.99O2 was synthesized using a conventional solid-state reaction method and sintered at 1400 & DEG;C for 2 h. The pure phase of the rutile TiO2 structure with a highly dense microstructure was obtained. A high dielectric permittivity (2.9 x 10(4) at 10(3) Hz) with a low loss tangent (< 0.025) was achieved in the as-sintered ceramic. After removing the outer surface, the dielectric permittivity of the polished ceramic increased from 2.9 x 10(4) to 6.0 x 10(4), while the loss tangent also increased (~0.11). The dielectric permittivity and loss tangent could be recovered to the initial value of the as-sintered ceramic by annealing the polished ceramic in air. Notably, in the temperature range of -60-200 & DEG;C, the dielectric permittivity (10(3) Hz) of the annealed ceramic was slightly dependent (<& PLUSMN;4.4%), while the loss tangent was very low (0.015-0.036). The giant dielectric properties were likely contributed by the insulating grain boundaries and insulative surface layer effects.

Automated summary

The Mg2+/Ta5+ codoped rutile TiO2 ceramic exhibited high dielectric permittivity and low loss tangent, with the properties being recoverable to the initial values through annealing. The giant dielectric properties were attributed to insulating grain boundaries and insulative surface layer effects.