压电陶瓷的极化反转过程

Polarization Reversal Process in Piezoelectric Ceramics

利用阻抗分析仪和重复迭代法，对Pb（Mg1／3Nb2／3）0.125Ti0．42Zr0．455O3压电陶瓷的极化反转过程进行了研究。实验数据显示出了铁电畴随电场变化的整个开关过程，发现极化反转前后压电性有着明显的不对称性，这一异常现象是和场诱应变、电滞回线数据相互对应的。经比较研究后认为，影响极化反转前后压电对称性的机理是空间电荷在晶粒表面积聚形成内偏置电场，由此建立的理论模型可以作出合理的解释。

By means of impedance analyzer and iterative method, the polarization reversal process of Pb (Mg1/3Nb2/3)0.125Ti0.42Zr0.455O3 piezoelectric ceramics was investigated in this paper. The experimental results figured out the entire process of ferroelectric domains switching with electric field. Compared the piezoelectricity before reversal with that after reversal, an evident asymmetry was observed, this phenomenon was in correspondence with field induced strain and D-E hysteresis loop. After taking a careful consideration, we think,the mechanism of piezoelectric asymmetry is due to internal bias field formed by space charges accumulated on the grain surface, the theoretical model building on this mechanism can play a reasonable explanation.