压电材料中缺陷偶极子特性的研究进展

Recent Progress on Defect Dipoles Characteristics in Piezoelectric Materials

压电材料通过受主掺杂或烧结挥发等可以形成缺陷偶极子,缺陷偶极子对材料的性能有显著的影响。本文综述了压电材料中缺陷偶极子的产生及其在外场下的响应机理,同时,从缺陷偶极子运动的角度分析了压电材料中老化、电滞回线异常及电致形状记忆效应等现象的起源,简要分析了偶极子弛豫现象,并对未来发展高可靠性压电驱动器的研究作了展望。

Defect dipoles which have pronounced effects on properties of piezoelectric materials can be introduced either by partially modifying with acceptor impurities or volatizing of cation elements in perovskite lattice during sintering. The formation mechanism of defect dipoles and responses under external fields were reviewed in the present paper. Besides, the main physic mechanisms of ferroelectric aging, hysteresis loop abnormalities and electro- shape-memory effects in piezoelectric materials were discussed in detail from the defect dipoles viewpoints. Based on a defect mediated reversible domain switching mechanism, large recoverable electro-strain, as well as constricted hysteresis loops were obtained in unpoled aged ferroelectric crystals and/or ceramics, which indicated that aging was not always a detrimental effect, and may be promising for future novel applications. Furthermore, the defect dipole relaxation process was briefly described and the development trends of the high reliability piezoelectric actuators were proposed.