標題: Strain-driven phase boundaries in BiFeO(3) thin films studied by atomic force microscopy and x-ray diffraction
作者: Liu, Heng-Jui
Liang, Chen-Wei
Liang, Wen-I
Chen, Hsiang-Jung
Yang, Jan-Chi
Peng, Chun-Yen
Wang, Guang-Fu
Chu, Feng-Nan
Chen, Yi-Chun
Lee, Hsin-Yi
Chang, Li
Lin, Su-Jien
Chu, Ying-Hao
材料科學與工程學系
Department of Materials Science and Engineering
公開日期: 17-Jan-2012
摘要: We report a detailed study on the strain-driven phase transition between the tetragonal-like and rhombohedral-like phases in epitaxial BiFeO(3) (BFO) thin films which focuses on their structural nature, thermodynamic stability, and ferroelectric/piezoelectric properties. We first show that the tetragonal-like phase, which has a large c/a ratio (similar to 1.2), in the compressively strained BFO is thermodynamically more favorable at high temperature and high strain state (small thickness). We also report a phase transition between two monoclinic phases at 150 degrees C. The two monoclinic phases are differentiated by their c-axis parameters and tilting angles: The low-temperature phase (M(C)) has a c-axis parameter of 4.64 angstrom and a tilting angle (beta = 88.5 degrees) along the a axis, while the high-temperature phase (M(A)) has a c-axis parameter of 4.66 angstrom and a tilting angle (beta = 86.8 degrees) along both of the a and b axes. We further show that samples undergoing the M(C)-M(A) phase transition exhibit ferroelectric polarization rotation and piezoelectric enhancement. Our findings directly unveil the close links between structural changes, polarization rotation, and large piezoelectricity at morphotropic phase boundaries in BiFeO(3).
URI: http://dx.doi.org/10.1103/PhysRevB.85.014104
http://hdl.handle.net/11536/15254
ISSN: 1098-0121
DOI: 10.1103/PhysRevB.85.014104
期刊: PHYSICAL REVIEW B
Volume: 85
Issue: 1
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