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Direct Observation of Thickness Dependence of Ferroelectricity in Freestanding BaTiO 3 Thin Film
Author(s) -
Li Yueliang,
Yu Rong,
Zhou Huihua,
Cheng Zhiying,
Wang Xiaohui,
Li Longtu,
Zhu Jing
Publication year - 2015
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.13749
Subject(s) - materials science , ferroelectricity , transmission electron microscopy , tetragonal crystal system , thin film , polarization (electrochemistry) , distortion (music) , optics , optoelectronics , dielectric , nanotechnology , crystallography , crystal structure , chemistry , amplifier , physics , cmos
In this work, we focus on the thickness dependence of the electric polarization in a freestanding BaTiO 3 thin film. The locations of titanium and oxygen ions as well as their relative displacements were directly observed and measured by using aberration‐corrected transmission electron microscopy (AC‐TEM). It is found that the freestanding BaTiO 3 thin film keeps the tetragonal distortion when its thickness is thicker than 4.8 nm, while completely loses its ferroelectricity when thinner than 4.4 nm. The method of combining high‐resolution AC‐TEM imaging with the multiparameter simulation unit cell by unit cell was developed to accurately determine each local thickness of the sample. This method is powerful for quantitative analysis in AC‐TEM images.