Role of oxygen vacancy on the electrical properties of SnO2-Zn2SnO4 ceramic composites with the introduction of Nb2O5 oxide

Abstract In this work, the role of oxygen vacancy on the electrical properties of traditionally prepared SnO 2 -Zn 2 SnO 4 ceramic composites was evaluated by introducing Nb 2 O 5 oxide. With increasing Nb 2 O 5 content, the breakdown electric field E 1.0 and the relative permittivity e r measured at low frequencies increased and declined, respectively. In the microstructure photos, the grain size decreased before reaching a saturation point. In addition, Nb was randomly distributed in the grains and along grain boundaries. By doping Nb 2 O 5 , the color of the sintered samples darkened, and F-type color centers were generated. In the complex electric modulus spectra, the peak of the imaginary part M ″ shifted toward a lower frequency; whereas, the activation energy E a changed slightly with increasing Nb 2 O 5 content. The results suggest that oxygen vacancy is the origin of the varistor and high permittivity properties of SnO 2 -Zn 2 SnO 4 ceramic composites. Furthermore, the varistor and dielectric properties can be modulated by changes in the microstructure.