Dielectric Properties and Relaxation Behaviors of ZrO2 Doped Sr0.97Sm0.02TiO3 Ceramics

The Sr0.97Sm0.02TiO3 (SSTO) ceramics were prepared by solid state reaction method with the relative dielectric constant of 3681 and a low dielectric loss less than 0.02 (measured at 1kHz and room temperature). The SSTO ceramics with ZrO2 addition have been studied to improve the performance stability under the bias field. The grain size of the ceramics decreases with the ZrO2 added. An excellent dielectric properties are obtained at the sample with 1wt% ZrO2 added with the variation of dielectric loss of 7 % at the 0-20kV/cm, which is better than that of SSTO ceramics (30 % at the 0-20kV/cm). The dielectric constant of SSTO ceramics with 1wt% ZrO2 doping remains 3000 and the dielectric loss is less than 5 %. The relaxation behaviors of the ZrO2 doped SSTO ceramics were also investigated by post-annealing experiments and complex-impedance analysis, which indicate that the coupling of oxygen vacancies-strontium vacancies and the Maxwell-Wagner polarization are the origins of the relaxation behaviors.