Dielectric relaxation in amorphous and amorphous-crystalline lead titanate

The effect of thermal annealing on processes of dielectric relaxation and dielectric properties of amorphous and amorphous-crystalline lead titanate within the temperature range, including the crystallization temperature was studied. Two anomalies of losses in a temperature range ∼200-460°C were found. The first one is probably related to making free of traps, and second one is due to presence of polar regions and their interaction with mobile charge carriers. The d.c. field effect on dielectric permittivity of amorphous sample mainly related to increasing of its conductivity under high electric field. The analysis of time dependences of dielectric permittivity shows two mechanisms of crystallization.