Thickness-dependent twinning evolution and ferroelectric behavior of epitaxial BiFeO3 (001) thin films
Thickness-dependent twinning evolution and ferroelectric behavior of epitaxial BiFeO3 (001) thin films
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外延 BiFeO3 (001) 薄膜的厚度依赖性孪晶演化和铁电行为
DOI：
10.1103/physrevb.82.064108
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发表时间：
2010-08-19
影响因子：
3.7
通讯作者：
Wang, John
中科院分区：
文献类型：
--
作者：
Liu, Huajun;Yao, Kui;Wang, John
随着生长在钛酸锶衬底上的BiFeO_3(001)外延薄膜的厚度从30 nm增加到720 nm，晶体结构由完全应变的四方晶格演化为部分弛豫的旋转孪晶单斜晶格。尽管失配应变导致了显著的晶格扭曲和孪晶演化，但极化与应变并没有显示出直接的相关性。相反，极化强烈地依赖于扭曲的伪立方单胞的身体对角线长度。除应变外，偏振方向的变形是决定单斜相铁电薄膜偏振的关键参数。
With increasing film thickness of the epitaxial BiFeO3 (001) films deposited on SrTiO3 substrates from 30 to 720 nm, the crystal structure evolutes from a fully strained tetragonal lattice to partially relaxed monoclinic one with rotated twins. Although the mismatch strain results in a significant lattice distortion and twinning evolution, the polarization does not show a direct correlation with strain. Instead, there is a strong dependence of polarization on the body diagonal length of the distorted pseudocubic unit cell. The distortion in the polarization direction is the critical parameter, other than strain, that determines the polarization in the monoclinic phase ferroelectric thin films.