Structural phase transitions in BaPrO{sub 3}

Journal Article · Thu Apr 02 04:00:00 EDT 2009 · Materials Research Bulletin

DOI:https://doi.org/10.1016/j.materresbull.2008.09.013· OSTI ID:21199738

Saines, Paul J ^[1]; Smith, Ronald I ^[2]

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1. School of Chemistry, University of Sydney, Sydney, New South Wales 2006 (Australia)
2. ISIS Facility, Rutherford Appleton Laboratory, Chilton, Harwell Science and Innovation Campus, Didcot OX11 0QX (United Kingdom)

The crystal structures adopted by BaPrO{sub 3} at and above ambient temperature have been examined using a combination of synchrotron X-ray and neutron diffraction. BaPrO{sub 3} has been established to undergo a series of phase transitions from Pbnmorthorhombic{yields}Ibmmorthorhombic{yields}R3-bar crhombohedral{yields}Pm3-barm cubic. BaPrO{sub 3} is the second A{sup 2+}B{sup 4+}O{sub 3} perovskite found to adopt rhombohedral symmetry in preference to the I4/mcm tetragonal structure. Analysis of the octahedral tilting through the rhombohedral to cubic phase transition indicates that this transformation is continuous and tricritical in nature. The tricritical behaviour of this transition is likely to be a result of the competition between tetragonal and rhombohedral structures to be the preferred phase, with the rhombohedral symmetry adopted by BaPrO{sub 3} being stabilised by the unusually large B-site cation.

• OSTI ID: 21199738
• Journal Information: Materials Research Bulletin, Journal Name: Materials Research Bulletin Journal Issue: 4 Vol. 44; ISSN MRBUAC; ISSN 0025-5408
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AMBIENT TEMPERATURE
CUBIC LATTICES
NEUTRON DIFFRACTION
OXIDES
PEROVSKITE
PHASE TRANSFORMATIONS
TETRAGONAL LATTICES
TRIGONAL LATTICES
X-RAY DIFFRACTION