Dielectric properties and high tunability of Ba(Ti0.7Zr0.3)O3 ceramics under dc electric field

The effect of dc electric field (E) on the dielectric properties of Ba(Ti0.7Zr0.3)O-3 ceramics with an obvious ferroelectric-relaxor behavior (T(m)similar to229 K, 10 kHz) is reported. The dielectric constant is greatly suppressed and a low loss is obtained under dc electric fields (less than or equal to40 kV/cm). The low loss (tan deltasimilar to0.002) and high tunability (similar to45%) were obtained for the Ba(Ti0.7Zr0.3)O-3 ceramics around 300 K, indicating that it is a promising candidate for tunable materials at room temperature. The field dependence of the temperature (T-m) of the dielectric constant maximum follows the DeltaT(m)similar toE(2/3) relation, indicating a second-order phase-transition-like behavior. (C) 2002 American Institute of Physics.