Dielectric stability in the relaxor: Na0.5Bi0.5TiO3-Ba0.8Ca0.2TiO3-Bi(Mg0.5Ti0.5)O3- NaNbO3 ceramic system

Ceramics with temperature-stable dielectric characteristics have been developed in the system: 0.6[0.85Na0.5Bi0.5TiO3-(0.15-x)Ba0.8Ca0.2TiO3-xBi(Mg0.5Ti0.5)O3]−0.4NaNbO3, x ≤ 0.15. Dielectric measurements exhibited relaxor ferroelectric characteristics with temperature-stable relative permittivity from εr~1330 ± 15% in the temperature range from −70 °C to 215 °C and tanδ ≤ 0.02 from −20 °C to 380 °C for x = 0 compositions. For the Bi(Mg0.5Ti0.5)O3 modified compositions the temperature range of stable relative permittivity extended from −70 °C to 400 °C, with εr ~ 950 ± 15% and tanδ ≤ 0.02 from −70 °C to 260 °C. Values of dc resistivity were ~ 108 Ω m at a temperature of 300 °C and the corresponding RC constant values were in the range from 0.40 − 0.78 s at 300 °C. All ceramic samples exhibited a linear polarisation-electric field response at maximum applied electric field of 5 kV/cm (1 kHz).