Effect of single point defect on local properties in BiFeO3 thin film. (15th May 2019)

• Record Type: Journal Article
• Authors: Li, Xiaomei; Li, Mingqiang; Li, Xuanyi; Tian, Shilu; Abid, Adeel Y.; Li, Ning; Wang, Jianlin; Zhang, Lei; Li, Xujing; Zhao, Yanchong; Wang, Can; Xu, Zhi; Meng, Sheng; Gao, Peng; Bai, Xuedong
• Is Part Of: Acta materialia. Volume 170(2019)
• Page Start: 132
• Page End: 137
• Publication Date: 2019-05-15
• Subjects: Ferroelectric -- Point defect -- Scanning transmission electron microscopy -- Quantitative image analysis -- Density function calculations; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2019.03.028
• Languages: English
• ISSNs: 1359-6454

Abstract

Abstract: Point defects commonly exist in artificially prepared ferroelectric oxide films. Here, the local polarization characteristics around a single point defect of Bi substitution in the Fe sites (antisite Bi, BiFe ) in BiFeO3 (BFO) thin film, are studied at an atomic scale. Both first-principles theory and atomically resolved scanning transmission electron microscopy images show that a single point defect expands the lattice (∼2.4% in-plane direction and 0.8% along out-of-plane direction) but suppresses the surrounding polarization by more than ∼27%. The suppression of polarization is due to the formation of a single unit cell of non-ferroelectric Bi2 O3, across which the accumulation of polarization bound charge induces a strong depolarization field. Therefore, structure relaxation makes the Bi2 O3 coherently polarized and meanwhile suppresses the surrounding polarization. Such point defects act as a pinning center to domain wall motion, which gives rise to incomplete switching, fatigue, and aging of ferroelectric devices. Graphical abstract: Image 1