High nonlinearity and low leakage current SnO2 varistor ceramics by co-doping with yttrium and tantalum

Abstract

We report on co-doping of tantalum and yttrium into SnO2 varistors. The electrical parameters of the prepared devices show that a moderate tantalum doping level reduces the leakage current while maintaining a high voltage gradient and excellent nonlinearity. Yttrium and tantalum doping levels of 0.05 mol% and 0.003 mol%, respectively, gave the best electrical performance, including a nonlinear coefficient of 54, leakage current of 3.2 μA/cm2 and voltage gradient of 485 V/mm.