Dielectric tunability of (Ba0.90Ca0.10)(Ti0.75Zr0.25)O3 ceramics

Abstract

We have performed a study on the dielectric properties of (Ba0.90Ca0.10)(Ti0.75Zr0.25)O3 bulk ceramics prepared by a sol–gel technique in the cooling temperature range from 400to213K. The ceramics are found to exhibit an interesting dielectric response under the presence of a dc bias field. The field dependence of dielectric constant is stronger at T≈Tm (Tm is the temperature of dielectric maximum) and the field-induced variation of dielectric constant Δε is nonzero for T−Tm<150K. One striking feature of these ceramics is that they possess a broad optimum value of figure of merit (as high as 200 at 30kV∕cm) between the temperature range from 295 and 330K. At room temperature, the high tunability (K=60%), low-loss tangent (≈0.003), and large figure of merit (200), clearly indicate that these ceramics are suitable candidates for microwave applications.