@article{ec27f72fd7f443338b5d24532dfbbe6a,
title = "Ferroelectricity mediated by ferroelastic domain switching in HfO2-based epitaxial thin films",
abstract = "Herein, ferroelastic domain switching from the nonpolar b-axis to the polar c-axis oriented domain in 7%-YO1.5-substituted HfO2 (YHO-7) epitaxial ferroelectric films is demonstrated. Scanning transmission electron microscopy (STEM) indicates that the polarization of a pristine film deposited on a Sn-doped In2O3/(001)YSZ substrate by the pulsed laser deposition method tends to be along the in-plane direction to avoid a strong depolarization field with respect to the out-of-plane direction. Applying an electric field aids in ferroelastic domain switching in YHO-7 films. Such films exhibit ferroelectric characteristics with a relatively large saturated polarization around 30 μC/cm2 by polarization reorientation from the in-plane to the out-of-plane directions and an increased dielectric constant. The synchrotron X-ray diffraction measurements with a focused beam for the pristine and poled area indicate ferroelastic 90° domain switching as the odd number reflection disappears, which is only allowed in the nonpolar b-axis orientation. STEM observations also show a significant increase in the c-axis oriented domain. This observation of ferroelastic domain switching strongly supports the conclusion that the ferroelectricity of HfO2 originates from the non-centrosymmetric orthorhombic phase.",
author = "Takao Shimizu and Takanori Mimura and Takanori Kiguchi and Takahisa Shiraishi and Toyohiko Konno and Yoshio Katsuya and Osami Sakata and Hiroshi Funakubo",
note = "Funding Information: This work was financially supported by the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT) through the Element Strategy Initiative to Form Core Research Center and Japan Society for the Promotion of Science (JSPS) KAKENHI Grant Nos. 17K14807, 17J10208, and 18H01701. The synchrotron radiation XRD experiments were performed at the BL15 of SPring-8 with the approval of the NIMS Beamline Station (Proposal Nos. 2015A4702, 2015B4702, 2016A4702, and 2017B4701). Funding Information: This work was financially supported by the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT) through the Element Strategy Initiative to Form Core Research Center and Japan Society for the Promotion of Science (JSPS) KAKENHI Grant Nos. 17K14807, 17J10208, and 18H01701. The synchrotron radiation XRD experiments were performed at the BL15 of SPring-8 with the approval of the NIMS Beamline Station (Proposal Nos. 2015A4702, 2015B4702, 2016A4702, and 2017B4701). A part of this study was supported by Tohoku University Microstructural Characterization Platform in Nanotechnology Platform Project sponsored by MEXT, Japan. Publisher Copyright: {\textcopyright} 2018 Author(s).",
year = "2018",
month = nov,
day = "19",
doi = "10.1063/1.5055258",
language = "English",
volume = "113",
journal = "Applied Physics Letters",
issn = "0003-6951",
publisher = "American Institute of Physics",
number = "21",
}
