Low variation in relative permittivity over the temperature range 25-450°C for ceramics in the system (1-x)[Ba0.8Ca0.2TiO3]-x[Bi(Zn0.5Ti0.5)O3]

The dielectric and ferroelectric properties of the ceramic system, (1-x)Ba0.8Ca0.2TiO3-xBi(Zn0.5Ti0.5)O3, were investigated for compositions 0≤x≤0.4. X-ray powder diffraction patterns indicated tetragonal symmetry at x≤0.05, switching to pseudocubic at x≥0.1, with a single-phase solid solution limit at 0.2<x<0.3. The x=0 and 0.05 samples were ferroelectric; a change to relaxor behaviour occurred at x≥0.1, with broad frequency dependent peaks in plots of relative permittivity versus temperature. A significant reduction in the temperature dependence of relative permittivity occurred at x=0.3, with e{open};r=1030±15% over the temperature range ~25-425°C, and loss tangent, tanδ≤0.01 from 110°C to 420°C. The dc resistivity values for x=0.3 were ~109Ωm at 300°C and ~106Ωm at 450°C.