铁电体的极化疲劳和历史记忆效应

电滞回线是研究铁电性的重要方法,但其中非线性电导,非线性顺电电容等非铁电性的影响难以消除.为此提出了微分电滞回线方法以取代传统的电滞回线.基于该方法,可将回线中各种非铁电性的贡献定量地分离出来,从而得到纯铁电性的贡献.对锆钛酸铅(PZT)和钛酸钡(BST)陶瓷样品的测量结果表明,纯铁电微分回线可用若干个高斯函数精确拟和,铁电体的极化疲劳就表现为高斯函数个数、峰位、峰高、半高宽等参数在外加作用下持续变化.实验还进一步证明,疲劳效应与铁电体所经历的热力学历史密切相关.

Polarization Fatigue and History Memory Effect in Ferroelectrics

Dielectric hysteresis loop is an important method for the research of ferroelectricity, but there are non-ferroelectric effects, such as non-linear conductance, non-linear paraelectric capacitance, et al, to be separated. To get rid of this problem, a new method called differential hysteresis loop is introduced. Based on this method, some non-ferroelectric effects are quite easily to be separated, and the pure ferroelectric effect can be obtained. The experiments of PZT and BST ceramics reveal that pure ferroelectric differential loop can be accurately fitted by Gaussian functions, polarization fatigue can be described with the variations of the peak positions, heights, half height half widths of the Gaussian peaks. Moreover, the experiment proved that polarization fatigue effects relate closely to the sample' s thermodynamic history.