Phase transition in the Ruddlesden-Popper layered perovskite Li{sub 2}SrTa{sub 2}O{sub 7}

Journal Article · Sun Feb 15 00:00:00 EST 2009 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2008.10.029· OSTI ID:21212195

Pagnier, T; Rosman, N ^[1]; Galven, C ^[2]; Suard, E ^[3]; Fourquet, J L; Le Berre, F ^[2]

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1. LEPMI BP75 1130 rue de la Piscine F-38402 Saint Martin d' Heres (France)
2. LdOF, FR no 2575 IRIM2F, UMR CNRS 6010, Faculte des Sciences et Techniques, Universite du Maine, Avenue O. Messiaen 72017 Le Mans Cedex 9 (France)
3. Institut Lauee-Langevin, 6 rue G. Horowitz, 38042 Grenoble Cedex 9 (France)

The crystal structure of the Ruddlesden-Popper layered perovskite Li{sub 2}SrTa{sub 2}O{sub 7} has been characterized at various temperatures between -185 and 300 deg. C by several techniques: X-ray and neutron powder diffraction, single crystal diffraction, transmission electron microscopy and Raman spectroscopy. The low temperature structure has been confirmed to be orthorhombic Cmcm with a small octahedra antiphase tilting ({phi}{phi}0) ({phi}{phi}0) inside the perovskite blocks. With temperature, the tilting progressively vanishes leading around 230 deg. C to a tetragonal symmetry (S.G. I4/mmm). This reversible phase transition, followed by X-ray and neutron thermodiffraction and thermal Raman measurements, is considered as of second order. An attribution of the Raman bands based on normal mode analysis is proposed. - Graphical abstract: Thermal evolution of Li{sub 2}SrTa{sub 2}O{sub 7} X-ray powder diffraction patterns showing the structural transformation from orthorhombic to tetragonal cell.

• OSTI ID: 21212195
• Journal Information: Journal of Solid State Chemistry, Vol. 182, Issue 2; Other Information: DOI: 10.1016/j.jssc.2008.10.029; PII: S0022-4596(08)00529-X; Copyright (c) 2008 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
MONOCRYSTALS
NEUTRON DIFFRACTION
NORMAL-MODE ANALYSIS
ORTHORHOMBIC LATTICES
OXIDES
PEROVSKITE
PHASE TRANSFORMATIONS
RAMAN SPECTROSCOPY
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 0400-1000 K
TETRAGONAL LATTICES
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION