Phase transition behaviour in the A-site deficient perovskite oxide La{sub 1/3}NbO{sub 3}

Journal Article · Wed Dec 01 00:00:00 EST 2004 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2004.08.047· OSTI ID:20658232

Kennedy, Brendan J ^[1]; Howard, Christopher J ^[2]; Kubota, Yoshiki ^[3]; Kato, Kenichi ^[4]

---

1. Centre for Structural Chemistry and Biology, School of Chemistry, University of Sydney, F11, Sydney, New South Wales 2006 (Australia)
2. Australian Nuclear Science and Technology Organisation, Private Mail Bag 1, Menai, New South Wales 2234 (Australia)
3. Department of Environmental Sciences, Faculty of Science, Osaka Women's University, Daisen-cho 2-1, Sakai, Osaka 590-0035 (Japan)
4. Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Mikazuki-cho, Sayo-gun, Hyogo 679-5198 (Japan)

The crystal structure of the layered perovskite La{sub 1/3}NbO{sub 3} has been studied between room temperature and 500{sup o}C using synchrotron X-ray powder diffraction methods. The structure shows ordering of the La cations at all temperatures. At room temperature La{sub 1/3}NbO{sub 3} is orthorhombic with the NbO{sub 6} octahedra showing out-of-phase tilting about the a-axis. This tilting diminishes as the temperature increases, so that above 200{sup o}C the structure is tetragonal. The transition to the tetragonal structure is found to be continuous and analysis of the spontaneous strains shows it to be tricritical in nature.

• OSTI ID: 20658232
• Journal Information: Journal of Solid State Chemistry, Vol. 177, Issue 12; Other Information: DOI: 10.1016/j.jssc.2004.08.047; PII: S0022-4596(04)00472-4; Copyright (c) 2004 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
LANTHANUM COMPOUNDS
NIOBATES
ORTHORHOMBIC LATTICES
OXIDES
PEROVSKITE
PHASE TRANSFORMATIONS
TEMPERATURE RANGE 0273-0400 K
TETRAGONAL LATTICES
X-RAY DIFFRACTION