Dielectric Properties and Relaxation Behaviors of ZrO₂ Doped Sr_0.97Sm_0.02TiO₃ Ceramics

Abstract

The Sr_0.97Sm_0.02TiO₃ (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 1 kHz 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 1 wt% ZrO₂ added with the variation of dielectric loss of 7 % at the 0–20 kV/cm, which is better than that of SSTO ceramics (30 % at the 0-20 kV/cm). The dielectric constant of SSTO ceramics with 1 wt% 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.

Keywords:

• Dielectric properties
• relaxation
• oxygen vacancies
• Maxwell-Wagner polarization

Funding

This work was financially supported by National Key Basic Research Program of China (No. 2015CB654601), the National Natural Science Foundation of China (No. 51102189, No. 51372191), the Key Program of Natural Science Foundation of China (No. 50932004), the Program for New Century Excellent Talents in University (No. NCET-11-0685), the Fundamental Research Funds for the Central Universities (No. 2014-IV-134), the International Science and Technology Cooperation Program of China (2011DFA52680).