Effect of electric field on the dielectric properties and ferroelectric phase transition of sol–gel derived (Ba0.90Ca0.10)TiO3 ceramics

Barium calcium titanate (Ba0.90Ca0.10)TiO3 (BCT) ferroelectric ceramics were prepared from powders synthesized using a sol–gel process. The effects of dc electric field on the dielectric properties of BCT ceramics have been investigated in a cooling temperature from 190 to 40 °C. The results show that the maximum dielectric permittivity (ɛm) decreased from 4541 to 2935 when the applied dc field increase from 0 to 10 kV cm−1, and the temperature of the maximum dielectric permittivity (Tm) was almost unchangeable with increasing dc field. The phase temperature of unpoled and poled samples was the same near by 131 °C. The dielectric permittivity of unpoled and poled samples during heating and cooling were not equal, which resulted from the polarization state of the ferroelectric domains. The spontaneous polarization (Ps) and remanent polarization (Pr) of BCT ceramics were found to be 13.3 and 5.39 μC cm−2, respectively at 20 °C and 40 kV cm−1, and the Pr value was decreased linear with increase temperature from 20 to 150 °C.