陶瓷型铁电复合物厚片介电系数的电场依赖性

建立起高压介电测试装置和相应的数据处理方法。研究了PZT/P (VDF-T rFE) 和PT/P (VDF- rFE) 0-3型铁电复合物厚片介电系数的电场依赖性。对于陶瓷体积分数U> 0.3 的复合物, 介电系数随测试场强的升高明显增大。在U< 0.1 时, 可用M axw ell-Garnet t 方程拟合试验结果。B ruggeman 方程适合于低电场(< 1MV/m ) 下复合物介电系数的预测。通过L z 的变化, 用Yamada 模型可拟合复合物介电系数随电场变化的关系, 说明L z 是由复合物的组分维数、粒子形状以及粒子间静电相互作用所决定的参数。 

DEPENDENCE OF DIELECTRIC PERMITTIVITY ON ELECTRIC FIELD FOR THICK CERAMIC-TYPE FERROELECTRIC COMPOSITE FILMS

Measuring apparatus and data processing method of dielectric permittivity at high voltage have been set up. Dependence of dielectric permittivity on electric field for thick PZT/P(VDF TrFE) and PT/P(VDF TrFE) 0-3 ferroelectric composite films has been investigated. The dielectric permittivity increases obviously with the increase of applied field for the composite with the volume fraction of ceramic φ more than 0.3. Maxwell Garnett equation can only be used to predict permittivity of the composite when φ is less than 0.1. Bruggeman equation is suitable for the prediction of dielectric permittivity of composite under low electric field (<1 MV/m). For the dependence of dielectric permittivity on electric field, good agreement is found between the measured permittivity and the prediction of Yamada model with the change of parameter L z, which indicates that L z is determined by dimension of the component, grain shape and static interaction among the grains.