弛豫铁电多晶体的强场特性

CHARACTERISTICS OF FERROELECTRIC POLYCRYSTALLINE WITH DIFFUSE PHASE TRANSITION UNDER HIGH ELECTRIC FIELD STRENGTH

本文介绍了弛豫铁电多晶体的研究、发展及其电致伸缩性质。论文中比较了三种典型铁电弛豫体:PMN—PT、PLZT和掺杂BT多晶材料的强电场特性。实验发现,当温度偏离T_(av)时,PLZT多晶体出现越来越强的电滞后现象,导致其微位移器件的回零复原温度特性变坏。用电学方法,在碱土金属离子B位掺杂的BT多晶体中可以观察到超顺电相的所谓微畴——宏观畴的场诱相变过程。作者指出,化学缺陷控制原理可用于调节电致伸缩材料的强场特性,控制器件的复原特性。

A review of the research and developement of ferroelectric rel- axors,and their electrostrictive properties is given.A comparison between ferroelectric relaxors,PMN-PT,PLZT and dopped BaTiO_3, also is presented.when temperatures are far away from T_(av),strong dielectric hysteresis occurs for PLZT8.7/65/35 ceramic,and it is impossible for the recovery of the micropositionor/electrostrictor, which is made of the compositon,under a given electric field stre- lngth.A micro-domain to macro-domain transfer of dopped-BaTiO_3 could be observed with a dielectric method.It is shown that the high-electric field peoperties of ferroelectric relaxors may be adju- sted through the control of the chemical defect and also the recovery of the micropositonor in the displacement.