Enhanced ferroelectric and dielectric properties of (111)-oriented highly cation-ordered PbSc{sub 0.5}Ta{sub 0.5}O{sub 3} thin films

• Published in: Journal of applied physics 2013-12, Vol.114 (22)
• Main Authors: Chopra, Anuj, Faculty of Science and Technology, MESA Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, Birajdar, Balaji I., Special Centre for Nano Sciences, Jawaharlal Nehru University, New Delhi 110067, Kim, Yunseok, School of Advanced Materials Science and Engineering, Sungkyunkwan University, Alexe, Marin, Department of Physics, University of Warwick, Coventry CV4 7AL, Hesse, Dietrich
• Format: Article
• Language: English
• Subjects: CATIONS; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; DEPOSITS; ENERGY BEAM DEPOSITION; EPITAXY; FERROELECTRIC MATERIALS; LASER RADIATION; MATERIALS SCIENCE; PERMITTIVITY; POLARIZATION; PULSED IRRADIATION; PYROCHLORE; STRONTIUM TITANATES; THIN FILMS; TRANSMISSION ELECTRON MICROSCOPY; X-RAY DIFFRACTION
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.4846817

Cation-ordered (111)-oriented epitaxial PbSc{sub 0.5}Ta{sub 0.5}O{sub 3} (PST) thin films were deposited by pulsed laser deposition on SrRuO{sub 3}-electroded SrTiO{sub 3} (111) substrates at three different temperatures of 525 °C, 550 °C, and 575 °C. All the films were well crystalline and (111)-oriented at all the three growth temperatures; however, the films deposited at the temperatures other than 550 °C exhibited the presence of a pyrochlore phase. X-ray diffraction analysis and transmission electron microscopy measurements revealed that the films were epitaxial and highly cation-ordered. In comparison to (001)-oriented PST films, (111)-oriented films on SrRuO{sub 3}/SrTiO{sub 3} (111) exhibited enhanced ferroelectric and dielectric properties with a broad size distribution of cation-ordered domains (5–100 nm). At a measurement temperature of 100 K, the remnant polarization of PST (111) films is almost √3 times larger than the remnant polarization observed for (001)-oriented PST films, which is attributed to the (111) orientation of the films, as the spontaneous polarization in PST lies close to the [111] direction. The observed dielectric constant and loss at 1 kHz were around 1145 and 0.11, respectively. The dielectric constant is thus almost three times higher than for previously reported (001)-oriented PST thin films, most probably due to the enhancement in cation-ordering.