Effect of TiO_2 Doping on Microdefects and Electrical Properties of ZnO-Based Varistors

摘要

Positron lifetime spectrum and electrical property measurements were performed on ZnO-based ceramics doped with different contents of TiO_2. For ZnO-based ceramics with TiO_2 content less than 1.8 mol%, the mean positron lifetime of the ZnO-based ceramic decreases with increasing in TiO_2 content, and reaches a minimum value at 1.8 mol% TiO_2. As the TiO_2 content higher than 1.8 mol%, the mean positron lifetime increases with TiO_2 content. The ZnO-based varistor with 1.8 mol% TiO_2 exhibites an optimized varistor property; it has a relatively low leakage current IL, a relatively low breakdown voltage VB, and a relatively high nonlinear coefficient α. The effects of TiO_2 doping on microdefects and electrical properties of ZnO-based varistors were discussed.