Thickness dependence of polarization in ferroelectric perovskite thin films
Thickness dependence of polarization in ferroelectric perovskite thin films
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DOI：
10.1088/0022-3727/38/4/010
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发表时间：
2005-02-21
影响因子：
3.4
通讯作者：
Nan, CW
中科院分区：
文献类型：
--
作者：
Liu, G;Nan, CW
通过使用广义的Landau-Ginzburg-Devonshire 热力学理论明确计算了铁电钙钛矿薄膜的极化对膜厚度的依赖性。薄膜中的残余应力和应力松弛对厚度相关的偏振有显着影响。我们的计算表明，表面效应和约束效应之间的共存或竞争导致在有限纳米尺度上产生显着的尺寸效应。对于压缩应变钙钛矿薄膜尤其如此，其中有两个特征厚度，即 h(c)（几纳米），低于该厚度铁电性消失，和 h(m)（类似于 10h(c)），其中极化表现出最大值。理论结果很好地描述了可用的实验数据。
The dependence of the polarization of ferroelectric perovskite thin films on the film thickness is explicitly calculated by using a generalized Landau-Ginzburg-Devonshire thermodynamic theory. Both residual stress and stress relaxation in the films have a significant effect on the thickness-dependent polarization. Our calculations demonstrate that the coexistence or competition between the surface effect and the constraint effect results in significant size effects at a finite nanoscale. This is especially so for the compressively strained perovskite films, in which there are two characteristic thicknesses, i.e. h(c) (a few nanometres), below which the ferroelectricity disappears, and h(m) (similar to 10h(c)), where the polarization exhibits a maximum. The theoretical results describe the available experimental data quite well.