Domain wall motion and its contribution to the dielectric and piezoelectric properties of lead zirconate titanate films
Domain wall motion and its contribution to the dielectric and piezoelectric properties of lead zirconate titanate films
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DOI：
10.1063/1.1325005
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发表时间：
2001-01-15
影响因子：
3.2
通讯作者：
Hemker, KJ
中科院分区：
文献类型：
--
作者：
Xu, F;Trolier-McKinstry, S;Hemker, KJ
在这篇文章中，畴壁运动和非本征贡献的介电和压电响应的溶胶-凝胶衍生锆钛酸铅（PZT）薄膜的成分附近的准同型相界进行了研究。结果发现，虽然膜具有不同的厚度，晶粒尺寸，和优选的取向，类似的本征介电常数，获得所有膜之间的0.5和3.4 μ m厚。据估计，在室温下，约25%-50%的介电响应来自外部源。非本征贡献的PZT薄膜的介电常数主要归因于180度畴壁运动，这与膜厚和晶粒尺寸增加。在研究PZT薄膜的正、匡威纵向压电系数随应力或驱动电场的变化时，发现铁弹非180度畴壁运动是有限的。因此，非本征贡献的压电响应是小的细晶粒PZT薄膜（特别是那些在1.5 μ m的厚度）。然而，随着膜变得更厚（>5 μ m），观察到匡威压电系数和电驱动场之间的非线性行为。这表明在较厚的薄膜中，在高的外部激励下存在显著的铁电非180度畴壁运动。通过非180度畴变研究了非180度畴壁的活性。对于薄膜厚度小于2 μ m的细粒薄膜，非180度切换可以忽略不计。透射电子显微镜平面图显微照片证明在这些膜中的非180度域条纹，其中绝大多数颗粒的直径为50-100 nm，并显示出单组域条纹。两者合计，这些测量表明，钉扎的非180度畴壁是非常强的膜厚度小于2 μ m。在较厚的薄膜，非180度的域切换证明当极化场超过阈值字段。阈值电场随薄膜厚度的增加而减小，表明较厚的薄膜具有更多的非180度畴壁迁移率。非180度畴变在大晶粒PZT薄膜被发现是更容易和更显着的比在细晶粒PZT薄膜。(C)2001年美国物理学会。
In this article, domain wall motion and the extrinsic contributions to the dielectric and piezoelectric responses in sol-gel derived lead zirconate titanate (PZT) films with compositions near the morphotropic phase boundary were investigated. It was found that although the films had different thicknesses, grain sizes, and preferred orientations, similar intrinsic dielectric constants were obtained for all films between 0.5 and 3.4 mum thick. It was estimated that about 25%-50% of the dielectric response at room temperature was from extrinsic sources. The extrinsic contribution to the dielectric constant of PZT films was mainly attributed to 180 degrees domain wall motion, which increased with both film thickness and grain size. In studies on the direct and converse longitudinal piezoelectric coefficients of PZT films as a function of either stress or electric driving field, it was found that the ferroelastic non-180 degrees domain wall motion was limited. Thus extrinsic contributions to the piezoelectric response were small in fine grain PZT films (especially those under 1.5 mum in thickness). However, as the films became thicker (>5 mum), nonlinear behavior between the converse piezoelectric coefficient and the electric driving field was observed. This indicated that there was significant ferroelectric non-180 degrees domain wall motion under high external excitation in thicker films. The activity of the non-180 degrees domain walls was studied through non-180 degrees domain switching. For fine grain films with film thicknesses less than 2 mum, non-180 degrees switching was negligible. Transmission electron microscopy plan-view micrographs evidenced non-180 degrees domain fringes in these films, where the vast majority of grains were 50-100 nm in diameter and showed a single set of domain fringes. Taken together, these measurements suggest that the pinning of non-180 degrees domain walls is very strong in films with thickness less than 2 mum. In thicker films, non-180 degrees domain switching was evidenced when the poling field exceeded a threshold field. The threshold field decreased with an increase in film thickness, suggesting more non-180 degrees domain wall mobility in thicker films. Non-180 degrees domain switching in large grained PZT films was found to be much easier and more significant than in the fine grained PZT films. (C) 2001 American Institute of Physics.