Abstract
In this paper discussions on ZnO based varistor ceramics doped with different ratios of Y2O3 are presented. Analysis on the phase and microstructures of the samples indicates that an additional phase is detected in the samples doped with Y2O3, and the average grain size of the specimens decreases from about 9.2 µm to 4.5 µm, with an increase in the addition of Y2O3 from 0 mol% to 3 mol%. The corresponding varistor’s voltage gradient markedly increases from 462 V/mm to 2340 V/mm, while the nonlinear coefficient decreases from 22.3 to 11.5, respectively. Furthermore, the characteristics of deep trap levels in these ZnO samples are investigated by measuring their dielectric spectroscopies. The trap energy level and capture cross section evaluated by relaxation peak of the Cole-Cole plot vary slightly as the addition of Y2O3 increases. These traps may be ascribed to the intrinsic defects of ZnO lattice.
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Supported by the National Natural Science Foundation of China (Grant Nos.50425721 and 50737001) and the 11th Five-year Natural S&T Supporting Plan of China (Grant No. 2006 BAAO2A16)
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Liu, J., Hu, J., He, J. et al. Microstructures and characteristics of deep trap levels in ZnO varistors doped with Y2O3 . Sci. China Ser. E-Technol. Sci. 52, 3668–3673 (2009). https://doi.org/10.1007/s11431-009-0369-9
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DOI: https://doi.org/10.1007/s11431-009-0369-9