Influence of ZnSb2O6 Doping on Phase, Electrical and Dielectric Properties of ZnO Varistors

The present investigation reports the variations of the microstructure and electrical properties due to a change in the ZnSb₂O₆ content of ZnO varistors. The impact of the ZnSb₂O₆ additive on both microstructure and electrical properties in ZnO varistors is studied via the X-ray diffraction (XRD) and an impedance analyzer. Zn₇Sb₂O₁₂ spinel phase and single hexagonal ZnO phase are detected in ZnO varistors with the addition of ZnSb₂O₆. The ZnO varistors with 5 mol% ZnSb₂O₆ have the highest nonlinear coefficient (43.2) and the lowest leakage current density (3.96 A cm⁻²). The resistivity of grain boundary ρ_gb increases continuously with the increasing content of ZnSb₂O₆ as demonstrated by impedance measurements. Additionally, low values of dielectric loss at high frequencies suggest a ZnO varistor doped with ZnSb₂O₆ is suitable for high frequency device applications.