THE STUDY ON FERROELECTRIC THIN FILM MATERIALS FOR NON-VOLATILE MEMORY

利用平面耦合因子（kp）与极化电场（E）的关系和（002）峰的相对强度（I_2）评价了四方晶系PZT陶瓷的铁电畴结构<002>。我们提出了由15种模式组成的典型结构域。进一步，我们选取了这两种模式分别制作了90个和180个域的域配置模型。有人认为，极化引起的畴结构的变化可以用计算具有individula轴的面积变化来解释。因此，根据I_2、kp、归一化极化率与E的关系，估算了取向于c轴的磁畴总量<002>。从我们的磁畴结构模型中，证实了90 °磁畴旋转的两个峰和180 °磁畴旋转的一个峰。90 °畴变后，c方向畴变主要由180 °旋转引起.结果，90 Ω畴转换减少，180 Ω畴转换增加。我们相信我们对体相陶瓷畴结构的研究可能有助于理解PZT薄膜的退化特性。

Ferroelectric domain structures of tetragonal PZT ceramics were evaluated by the poling field (E) dependence of planar coupling factor (kp) and relative XRD intensity of (002) peak, I_<002>. We proposed typical domain configurations composed of 15 patterns. Furthermore, we picked out the two patterns to make a domain configuration model with 90ﾟ and 180ﾟ domains. It was thought that the change in the domain structure by poling could be explained to calculate the change in the area with the individula axis. Therefore, the total amount of the domains oriented to c axis was estimated by the relation between I_<002>, kp, normalized polarization and E.From our domain configuration model, it was confirmed that there were two peaks of 90ﾟ domain rotation and one peak of 180ﾟ domain rotation. After the 90ﾟ domain switching, the domains in c direction were changed mainly by 180ﾟ rotation. As a result, the 90ﾟ domain switching decreased and 180ﾟ domain switching increased. We believe our study on domain structures of bulk ceramics may be useful for understanding the degradation characteristics in PZT thin films.