Giant Dielectric Response up to High Frequency in Sm_1.75Sr_0.25NiO₄ Ceramics

Abstract

The crystalline structure and dielectric properties of nominal Sm _1.75 Sr _0.25 NiO ₄ ceramics are presented. Three phases, Sm _1.70 Sr _0.30 NiO ₄ , Sm ₂ O ₃ and NiO, are found in the present ceramics, and the abundances are 77.7(1.1) wt%, 19.2(3) wt% and 6.1(2) wt%, respectively. The temperature-stable giant dielectric constant over 60 000 even up to 5 MHz is observed in a broad temperature range. The modulus plots show that the giant dielectric constant should be originated from the contribution of the grain interior instead of grain boundary. Compared with the other giant dielectric constant materials, the present materials have the great potentiality in the practical application, especially for the high frequency application.

Keywords:

• Giant dielectric response
• high frequency
• nickelate

Acknowledgment

This work was supported by National Science Foundation of China under Grant Nos. 50702049 and 50832005, Chinese National Key Project for Fundamental Researches under Grant No. 2009CB623302.