Bi(Mg0.5Ti0.5)O-3-doped NaNbO3 ferroelectric ceramics: Linear regulation of Curie temperature and ultra-high thermally stable dielectric response

摘要

Sodium niobate (NaNbO3, NN)-based ferroelectric ceramics have been extensively studied owing to their anti-ferroelectric (AFE) nature. However, the dielectric properties of NN-based ceramics, which would be beneficial to capacitor devices, gain less research interest. In this study, (1 - x)NaNbO3-xBi(Mg as Ti-0.5)O-3 (NN-xBMT, x = 0, 0.01, 0.02, 0.03, 0.04, 0.05) ferroelectric ceramics were manufactured by a traditional solid state method. Structure and dielectric/ferroelectric properties were studied in detail by X-ray diffraction, dielectric spectrum as well as polarization-electric field hysteresis loops. All ceramic samples show an AFE P phase in the doping range. As x increases, the grain size of studied compositions gradually decreases from 5.36 mu m in x = 0 to 2.05 mu m in x = 0.05. In addition, the incorporation of BMT plays a regulatory role to the Curie temperature T-c of ceramic samples, which decreases almost linearly from 375 degrees C x = 0 to 216 degrees C x = 0.05 at a rate of 33 degrees C/1 at. %. However, the degree of diffusion for each composition does not change significantly. More importantly, ultra-high thermally stable dielectric responses in a wide temperature range are obtained in NN-xBMT. Especially in x = 0.03, its permittivity is around 500 at room temperature and shows a variation less than 4.4% from 30 to 150 degrees C. Our results may have some guiding significance for the preparation of NN-based ceramics with specific T-c, and are significantly important for capacitor applications requiring a wide temperature range stability.