Relaxations in Ba2BiTaO6 ceramics investigated by impedance and electric modulus spectroscopies

Impedance spectroscopy analysis of the dielectric properties of a Ba2BiTaO6 ceramic was performed in the temperature range from room temperature to 500 K. The sample was prepared using conventional solid state synthesis under air and the X-ray diffraction shows the presence of Ba5Ta4O15 as a minor secondary phase (0.09%). The impedance data clearly show contributions of the grain and grain boundary. The results indicate that the conduction in Ba2BiTaO6 is due to hopping of oxygen vacancies and that the impurities not influence the conduction mechanism.