Characterization of the dielectric relaxation for (–0.05) ceramics by impedance spectroscopy

Dielectric properties and impedance spectra of ( 1 − x ) Ba ( Ti 0.8 Sn 0.2 ) O 3 – x ( Na 0.5 Bi 0.5 ) TiO 3 ceramics with x = 0.01 –0.05 are investigated. The addition of ( Na 0.5 Bi 0.5 ) TiO 3 can bring about significant changes in the dielectric properties of Ba ( Ti 0.8 Sn 0.2 ) O 3 . Impedance/modulus analyses indicate that several dielectric processes in the system play important roles in the significant dielectric relaxational behaviors, which can be observed from the relaxation time τ . A transition region between relaxor behavior and dielectric relaxation behavior is observed for x = 0.01 –0.02. Further analysis on the activation energy ( E a ) of grains proves the existence of a phase transition, which lowers the activation energy of the grains by ∼0.5 eV. However, this transition does not influence E a for grain boundaries very considerably.