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Controllable Defect Driven Symmetry Change and Domain Structure Evolution in BiFeO3 with Enhanced Tetragonality
- Publication Year :
- 2019
-
Abstract
- Defect engineering has been a powerful tool to enable the creation of exotic phases and the discovery of intriguing phenomena in ferroelectric oxides. However, accurate control the concentration of defects remains a big challenge. In this work, ion implantation, that can provide controllable point defects, allows us the ability to produce a controlled defect-driven true super-tetragonal (T) phase with enhanced tetragonality in ferroelectric BiFeO3 thin films. This point defect engineering is found to drive the phase transition from the as-grown mixed rhombohedral-like (R) and tetragonal-like (MC) phase to true tetragonal (T) symmetry. By further increasing the injected dose of He ion, we demonstrate an enhanced tetragonality super-tetragonal (super-T) phase with the largest c/a ratio (~ 1.3) that has ever been experimentally achieved in BiFeO3. A combination of morphology change and domain evolution further confirm that the mixed R/MC phase structure transforms to the single-domain-state true tetragonal phase. Moreover, the re-emergence of R phase and in-plane stripe nanodomains after heat treatment reveal the memory effect and reversible phase transition. Our findings demonstrate the control of R-Mc-T-super T symmetry changes and the creation of true T phase BiFeO3 with enhanced tetragonality through controllable defect engineering. This work also provides a pathway to generate large tetragonality (or c/a ratio) that could be extended to other ferroelectric material systems (such as PbTiO3, BaTiO3 and HfO2) which may lead to strong polarization enhancement.
- Subjects :
- Phase transition
Condensed Matter - Materials Science
Materials science
Condensed matter physics
R-Phase
Materials Science (cond-mat.mtrl-sci)
FOS: Physical sciences
02 engineering and technology
010402 general chemistry
021001 nanoscience & nanotechnology
Polarization (waves)
01 natural sciences
Crystallographic defect
Ferroelectricity
0104 chemical sciences
Tetragonal crystal system
Ion implantation
Phase (matter)
General Materials Science
0210 nano-technology
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....da9d7c420876b4c585962b716336067e