Effect of strong bias fields on the dielectric response of Ba0.95Ca0.05TiO3 ferroelectric ceramics

Dielectric response of calcium-doped ceramics Ba0.95Ca0.05TiO3 was studied at different temperatures under stepwise action of a constant bias field and different sample prehistory. The microstructure of polarized and depolarized samples was studied using atomic force microscopy and scanning electron microscopy. The reverse dependences of the permittivity were obtained after preliminary holding at a constant temperature in the ferroelectric phase and without it. It was found that prolonged sample exposure at constant temperature enhanced the appearance of anomalies in the behavior of the permittivity reverse dependences due to contribution of the defective structure of the material (domain walls pinning and depinning).