Dielectric properties of (Yb_(0.5)Ta_(0.5))_xTi_(1-x)O_2 ceramics with colossal permittivity and low dielectric loss

摘要

High dielectric loss is one of the current obstacles to the application of dielectric materials. In this paper, we synthesized a new dielectric material, i.e., (Yb + Ta)-co-doped TiO_2 dielectric material. The (Yb_(0.5)Ta_(0.5))_xTi_(1-x)O_2 ceramics were synthesized by the solid-state reaction method. It has been found that (Yb_(0.5)Ta_(0.5))_xTi_(1-x)O_2 ceramics had a dense ceramic microstruc-ture, and (Yb_(0.5)Ta_(0.5))_xTi_(1-x)O_2 ceramics exhibited the rutile TiO_2 structure. All (Yb_(0.5)Ta_(0.5))_xTi_(1-x)O_2 ceramics exhibited low dielectric loss (＜0.1) and large dielectric constant (＞ 10~5). The optimal dielectric properties are obtained at a doping level of x = 0.05 with dielectric constant of 5.1 × 10~5 and dielectric loss of 0.037. Further study of the thermal stability of the dielectric properties was performed in the temperature range from - 50 to 250 °C, which indicates that the ceramic sample with x = 0.05 co-dopant concentration maintains good dielectric properties in the temperature range from -50 to 100 °C. XPS shows that high dielectric properties can be explained by the electron-pinned defect-dipole mechanism.