Effects of barium on the nonlinear electrical characteristics and dielectric properties of SnO2-based varistors

• 来源期刊: 中国物理（英文版）
• 关键词: varistors tin oxide electrical and dielectric properties barium carbonate
• 年，卷（期）: 2004,（11）
• 页码范围: 1936-1940
• 页数: 5页
• 语种: 英文

摘要

The effects of barium on electrical and dielectric properties of the SnO2·Co2Oa.Ta2O5 varistor system sintered at 1250℃ for 60min were investigated. It is found that barium significantly improves the nonlinear properties. The breakdown electrical field increases from 378.0 to 2834.5V/mm, relative dielectric constant (at 1kHz) falls from 1206 to 161 and the resistivity (at 1kHz) rises from 60.3 to 1146.5kΩ·cm with an increase of BaCO3 concentration from 0mol%to 1.00mol%. The sample with 1.00mol% barium has the best nonlinear electrical property and the highest nonlinear coefficient (α=29.2). A modified defect barrier model is introduced to illustrate the grain-boundary barrier formation of barium-doped SnO2-based varistors.