title: Depth resolved lattice-charge coupling in epitaxial BiFeO3thin film.
abstract: For epitaxial films, a critical thickness (tc) can create a phenomenological interface between a strained bottom layer and a relaxed top layer. Here, we present an experimental report of how the tcin BiFeO3thin films acts as a boundary to determine the crystalline phase, ferroelectricity, and piezoelectricity in 60 nm thick BiFeO3/SrRuO3/SrTiO3substrate. We found larger Fe cation displacement of the relaxed layer than that of strained layer. In the time-resolved X-ray microdiffraction analyses, the piezoelectric response of the BiFeO3film was resolved into a strained layer with an extremely low piezoelectric coefficient of 2.4 pm/V and a relaxed layer with a piezoelectric coefficient of 32 pm/V. The difference in the Fe displacements between the strained and relaxed layers is in good agreement with the differences in the piezoelectric coefficient due to the electromechanical coupling.
authors.affiliation: School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Korea.
authors.forename: Hyeon Jun
authors.initials: HJ
authors.lastname: Lee
authors.affiliation: School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Korea.
authors.forename: Sung Su
authors.initials: SS
authors.lastname: Lee
authors.affiliation: School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Korea.
authors.forename: Jeong Hun
authors.initials: JH
authors.lastname: Kwak
authors.affiliation: Department of Energy Science, Sungkyunkwan University (SKKU), Suwon 16419, Korea.|Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Suwon 16419, Korea.
authors.forename: Young-Min
authors.initials: YM
authors.lastname: Kim
authors.affiliation: UNIST Central Research Facilities, Ulsan National Institute of Science and Technology, Ulsan 44919, Korea.
authors.forename: Hu Young
authors.initials: HY
authors.lastname: Jeong
authors.affiliation: Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States.
authors.forename: Albina Y
authors.initials: AY
authors.lastname: Borisevich
authors.affiliation: Pohang Accelerator Laboratory, Pohang 37673, Korea.
authors.forename: Su Yong
authors.initials: SY
authors.lastname: Lee
authors.affiliation: Department of Physics and Photon Science, Gwangju Institute of Science and Technology, Gwangju 61005, Korea.
authors.forename: Do Young
authors.initials: DY
authors.lastname: Noh
authors.affiliation: School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 16419, Korea.
authors.forename: Owoong
authors.initials: O
authors.lastname: Kwon
authors.affiliation: School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 16419, Korea.
authors.forename: Yunseok
authors.initials: Y
authors.lastname: Kim
authors.affiliation: School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Korea.
authors.forename: Ji Young
authors.initials: JY
authors.lastname: Jo