Back to Search
Start Over
Random local strain effects in the relaxor ferroelectric BaTi1−x Zr x O3: experimental and theoretical investigation
- Source :
- Phase Transitions, Phase Transitions, Taylor & Francis, 2011, 84 (5-6), pp.438-452. ⟨10.1080/01411594.2010.547153⟩, Phase Transitions, 2011, 84 (5-6), pp.438-452. ⟨10.1080/01411594.2010.547153⟩
- Publication Year :
- 2011
- Publisher :
- Taylor & Francis, 2011.
-
Abstract
- International audience; We report an investigation of the local structure in homovalent-substituted BaTi1−x Zr x O3 relaxors by a combination of experimental and theoretical methods, namely neutron total scattering, X-ray absorption spectroscopy, and supercell ab-initio calculations. It is shown that unlike Zr atoms, Ti atoms are largely displaced in their octahedra, and are thus associated with strong local dipole moments. Besides, we give evidence that the difference in the size of Ti4+ and Zr4+ cations leads to a significant size mismatch of the Ti-O6 and Zr-O6 octahedra. When they link to form the perovskite structure of BaTi1−x Zr x O3, the O6 octahedra undergo slight distortions in order to accommodate their different sizes. It is shown that they are compressed in the direction of Zr neighbors, and expanded in the direction of Ti neighbors. The polar Ti displacements, which are sensitive to the octahedral distortions, then become constrained in their orientation according to the local Zr/Ti distribution. Such constraints impede a perfect alignment of all the Ti displacements as existing in the classic ferroelectric BaTiO3. Our results shed light on the structural mechanisms that lead to disordered Ti displacements in BaTi1−x Zr x O3 relaxors, and probably in other BaTiO3-based relaxors with homovalent substitution.
- Subjects :
- 010302 applied physics
Relaxor ferroelectrics
Ferroelectrics
X-ray absorption spectroscopy
Pair distribution function
Materials science
Absorption spectroscopy
Condensed matter physics
Scattering
02 engineering and technology
[CHIM.MATE]Chemical Sciences/Material chemistry
021001 nanoscience & nanotechnology
01 natural sciences
Supercell ab-initio calculations
Dipole
Octahedron
Local structure
0103 physical sciences
Supercell (crystal)
General Materials Science
Neutron
0210 nano-technology
Instrumentation
Subjects
Details
- Language :
- English
- ISSN :
- 01411594 and 10290338
- Database :
- OpenAIRE
- Journal :
- Phase Transitions, Phase Transitions, Taylor & Francis, 2011, 84 (5-6), pp.438-452. ⟨10.1080/01411594.2010.547153⟩, Phase Transitions, 2011, 84 (5-6), pp.438-452. ⟨10.1080/01411594.2010.547153⟩
- Accession number :
- edsair.doi.dedup.....98991e84b8f7bce7680cf92a7e384e9f