Investigation of Dielectric Properties for Ba_0.4Sr_0.6TiO₃ Ceramics with Various Grain Sizes

Abstract

The effect of grain size on the dielectric properties of Ba_0.4Sr_0.6TiO₃ ceramics with various grain sizes in the range of 405–1635 nm was investigated. Diffusion phase transition and a tendency to lower dielectric nonlinearity were found when the grain size decreased to 405 nm. The dielectric tunability of sample with grain size of 405 nm was 2.83% at the electric field of 20 kV/cm, exhibiting the weakest dielectric nonlinearity. The dielectric breakdown strength as well as the energy storage density were enhanced obviously with the refinement of grain sizes in the range of 660–1635 nm, due to the insulation effect of increasing grain boundary density, exactly as the highest energy storage density with 1.7 J/cm³ for the sample with grain size of 660 nm.

Keywords:

• Grain size
• dielectric tunability
• energy storage density
• dielectric breakdown strength

Funding

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