Journal article
Controlling the phase transition in nanocrystalline ferroelectric thin films via cation ratio
Nanoscale, v 10(46), pp 21798-21808
14 Dec 2018
PMID: 30452041
Featured in Collection : UN Sustainable Development Goals @ Drexel
Abstract
Traditionally, the ferroelectric Curie temperature can be manipulated by chemical substitution, e.g., in Ba1-xSrxTiO3 as one of the archetypical representatives. Here, we show a novel approach to tune the ferroelectric phase transition applicable for nanostructured thin films. We demonstrate this effect in nano-grained BaTiO3 films. Based on an enhanced metastable cation solubility with Ba/Ti-ratios of 0.8 to 1.06, a significant shift of the phase transition temperature is discovered. The transition temperature increases linearly from 212 K to 350 K with increasing Ba/Ti ratio. For all Ba/Ti ratios, a completely diffused phase transition is present resulting in a negligible temperature sensitivity of the dielectric constant. Schottky defects are identified as the driving force behind the off-stoichiometry and the shift of the phase transition temperature as they locally induce lattice strain. Complementary temperature dependent Raman experiments reveal the presence of the hexagonal polymorph in addition to the perovskite phase in all cases. Interestingly, the hexagonal BaTiO3 influences the structural transformation on the Ba-rich side, while on the Ti-rich side no changes for the hexagonal polymorph at the ferroelectric transition temperature are observed. This concerted structural change of both polymorphs on the Ba-rich side causes a broad phase transition region spanning over a wide range up to 420 K including the transition temperature of 350 K obtained from dielectric measurements. These findings are promising for fine adjustment of the phase transition temperature and low temperature coefficient of permittivity.
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Details
- Title
- Controlling the phase transition in nanocrystalline ferroelectric thin films via cation ratio
- Creators
- Iryna S. Golovina - Drexel UniversityMatthias Falmbigl - Drexel UniversityChristopher J. Hawley - Drexel UniversityAnthony J. Ruffino - Drexel UniversityAleksandr V. Plokhikh - Drexel UniversityIgor A. Karateev - Kurchatov InstituteThomas C. Parker - United States Army Research LaboratoryAlejandro Gutierrez-Perez - Drexel UniversityAlexandre L. Vasiliev - United States Army Research LaboratoryJonathan E. Spanier - Drexel University
- Publication Details
- Nanoscale, v 10(46), pp 21798-21808
- Publisher
- Royal Soc Chemistry
- Number of pages
- 11
- Grant note
- DMR 1608887 / NSF; National Science Foundation (NSF) N00014-15-11-2170 / Office of Naval Research
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Materials Science and Engineering; Mechanical Engineering and Mechanics
- Web of Science ID
- WOS:000451772500022
- Scopus ID
- 2-s2.0-85057475625
- Other Identifier
- 991019169515904721
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- Collaboration types
- Domestic collaboration
- International collaboration
- Web of Science research areas
- Chemistry, Multidisciplinary
- Materials Science, Multidisciplinary
- Nanoscience & Nanotechnology
- Physics, Applied