CRYSTAL CHEMICAL STUDY ON 90°DOMAIN SWITCHING PEROVSKITE TYPE FERROELECTRICS

有两个域结构， 180度域和90度域，在四角异性非铁电子学中。90度的域可以被外部电磁场重新定位。90度的域重新定向指的是紧张和极化中的变化，因此，它对铁电材料的实际应用具有重要意义，并对合理化的行为有一定的影响。本研究旨在实现基于晶体化学字符在主钛（PT）基材料和主钛-铅氧化锆固体解决方案（PZT）的晶体结构和属性之间的关系，研究了具有不同三铁矿（Pb， R）TiO-D23-D2（R=Ca， Sr， Ba）的陶瓷学与不同三铁矿（c/a比率）。它发现了一个共同领域，该领域决定了域重新定位的容易程度取决于c/a比率，而固有的极化则取决于alkali地球元素的合并而成PT。The （Pb，Sr）TiOイイD23イエD2 showed the largest spontaneous polarization in the three specimens with c/a ratio = 1. 03。在根据固有极化中差异的起源的情况下，水晶结构分析已被携带出来使用Rietveld方法。分析结果表明，在立方体超声波结构的理想位置上，钛离子的置换是最大的（Pb， Sr）Tio-D23-D2，解释了较大的基质极化化; PZT陶瓷中90度域的动态行为是从测量频率对电场的频率依赖性施加的约束使用Mach-Zehnder型激光干扰仪的方法中测量的。这是发现的，因为重新定向有一个速度限制，在加利福尼亚州也有一个压电电气放松。10千赫。这一方法给出了90度域对压电线的贡献的信息。

There are two domain structures, 180 degree domains and 90 degree domains, in tetragonal perovskite type ferroelectrics. The 90 degree domains can be reorientated by an external electric field. The 90 degree domain reorientation induces the changes in strain and polarization, therefore, it is very important to understand the behavior of the reorientation for practical application of ferroelectric materials. This study was carried out for the purpose of understanding crystal chemical characters dominating the 90 degree domain- reorientation behaviors in lead titanate (PT)-based materials and lead titanate-lead zirconate solid solutions (PZT).The relationship between the crystal structures and properties was investigated for (Pb, R)TiOィイD23ィエD2(R=Ca, Sr, Ba) ceramics with different tetragonarity (c/a ratio). It was found that the coercive field which determines the easiness of the domain-reorientation depended on the c/a ratio, while the spontaneous polarization was depended on the alkali earth elements incorporated into PT. The (Pb,Sr)TiOィイD23ィエD2 showed the largest spontaneous polarization in the three specimens with c/a ratio = 1.03. In order to understand the origin of the difference in the spontaneous polarization, the crystal structure analysis was carried out using the Rietveld method. The result of analysis indicated that the displacement of Ti ion from the ideal position of cubic perovskite structure was largest in (Pb, Sr)TiOィイD23ィエD2, which explained the large spontaneous polarization.The dynamic behavior of the 90 degree domain-reorientation in PZT ceramics was investigated from the measurement of the frequency dependence of electric field induced strains using a Mach-Zehnder type laser interferometer. It was found that the reorientation had a velocity limit and a piezoelectric relaxation was observed at ca. 10kHz. This method gave the information of the contribution of 90 degree domain reorientation to the piezoelectric strains.