Oxygen-vacancy-related high-temperature dielectric relaxation and electrical conduction in 0.95K0.5Na0.5NbO3–0.05BaZrO3 ceramic

The crystal structure and dielectric properties of 0.95K0.5Na0.5NbO3–0.05BaZrO3 (KNN–BZ) ceramic have been investigated by X-ray diffraction and dielectric measurement. A rhombohedral distortion was caused and the dielectric permittivity near Curie temperature was significantly enhanced by introducing BZ into KNN. The dielectric and conductivity properties of the sample were studied by using AC impedance spectroscopy and universal dielectric relaxation law in detail. The typical high-temperature dielectric relaxation process was confirmed to be related to the oxygen vacancies inside the ceramic. The effect of lattice distortion on the activation energy for oxygen vacancy migration in KNN–BZ was discussed by comparing with KNN and KNN–BaTiO3.