PTCR陶瓷中的电阻率反常现象

Abnormal Resistance Properties in PTCR Barium Titanate

本文叙述了在50kHz以上高频域内，发现钛酸例基PTCR陶瓷材料Ba0.93Sr0.03Ca0.04TiO3＋xmolY2O3＋1wt％AST的高频电阻-温度特性曲线呈现负突变的反常现象．对于这一反常现象，本文用PTCR陶瓷的晶粒-晶界二层电介质模型分析了不同频率下的电学等效电路，从而解释了上述现象．利用上述等效电路，还解释了该材料在100Hz至5MHz的频率范围内有效介电系数温度谱随频率增加而出现峰分裂的现象，以及电容损耗温度谱随频率变化的原因．

In this paper the resistance properties of PTCR barium titanate [Ba0.93Sr0.03Ca0.04 TiO3＋xmolY2O3＋1wt% AST] were measured near Curie-temperature by a complex impedance analyzer(HP4192A) from 10Hz to 10MHz. It was observed that PTCR sample exhibits an abnormal negative-temperature- coefficient in frequencies higher than 50kHz. This phenomenon can be simply explAlNed by the two dielectric-layer model, and with this model, the behavior of effectivedielectric constant and its loss in wide frequency range can be explAlNed as well.