Structural instabilities in LnGaO3 perovskites at high pressures

Anatoliy Senyshyn 1,2Jens M. Engel 1,3Iain Oswald 4,5Leonid Vasylechko 2Marek Berkowski 6

1. Technische Universität Darmstadt, Institute of Materials Science, Petersenstr. 23, Darmstadt 64287, Germany
2. Lviv Polytechnic National University, Semiconductor Electronics Department, Bandera Street, 12, Lviv 79013, Ukraine
3. Virginia Polytechnic Institute and State University, Blacksburg 24061, United States
4. European Synchrotron Radiation Facility (ESRF), Grenoble 38043, France
5. University of Edinburgh, Department of Chemistry, The King\'s Buildings, West Mains Rd, Edinburgh EH9 3JJ, United Kingdom
6. Polish Academy of Sciences, Institute of Physics, al. Lotników 32/46, Warszawa 02-668, Poland


Crystal structure – property relation for perovskite type materials attract an attention of investigators over very long time. A purposeful tailoring of their physical and chemical properties requires a detailed and systematic knowledge of crystal structure behaviour under various environmental conditions and chemical composition.
Recent studies [1] resulted in obvious indications that the relative compressibilities of the A and B sites in ABX3 perovskite structure play an important role in determining the pressure-induced structural changes of perovskites. In order to prove and extend this assumption, perovskite type rare-earth gallates LnGaO3, whose crystal structure and its thermal evolution were systematically studied in the broad temperature and composition ranges [2], seem to be well-suited objects for high pressure diffraction studies, i.e. a good link between in-situ temperature- and pressure-dependent structural properties can be established. At ambient conditions all LnGaO3 possess distorted GdFeO3 type of structure and undergo transformation to LaAlO3 structure type at elevated temperatures, where temperature of the phase transformation is proportional to tolerance factor. It is worth to mention that the high pressure phase of the first representative LaGaO3 has the same symmetry as the phase found at high temperatures, i.e. LaAlO3 structure type.
High pressure structural studies on perovskite type rare-earth gallates LnGaO3 can resolve the set of questions collected, like:
-    is the LaAlO3 structure type occurring in other LnGaO3 at high pressures?
-    are phase transformation and elastic modules depending on perovskite tolerance factor?
-    what is the agreement between experimental data and results of semiclassical simulations [3]?
In order to clarify those problems, six samples have been chosen for high pressure powder diffraction experiments, four orthogallates LaGaO3, CeGaO3, PrGaO3, NdGaO3 and two solid solutions La0.50Pr0.50GaO3 and La0.63Nd0.37GaO3 whose magnitude of perovskite lattice deformation is close to those of cerium gallate.
Data collection was performed in a transmission mode at beamline ID27 at ESRF (Grenoble, France) using MAR345 imaging plate detector. To fulfil the quasi-hydrostatic condition, the 4:1 methanol-ethanol mixture was used as a pressure medium for LaGaO3 and La0.50Pr0.50GaO3, whereas other samples were cryogenically embedded into high purity nitrogen. More than 150 diffraction patterns were collected in a broad pressure range from 0.0001 to 40 GPa and results of such studies will be presented in the current contribution.

1. R.J. Angel, J. Zhao, N.L. Ross, Phys. Rev. Lett. 95 (2005) 025503.
2. L. Vasylechko, A. Senyshyn, U, Bismayer, in: Handbook on the Physics and Chemistry of Rare Earths, ed. K. A. Gschneidner Jr., J.-C. Bunzli, and V. Pecharsky (Elsevier, Amsterdam), Vol. 39 (2008) in print.
3. A. Senyshyn, H. Ehrenberg, L. Vasylechko, J.D. Gale, U Bismayer, J. Phys.: Condens. Matter 17 (2005) 6217.

Legal notice
  • Legal notice:

    Copyright (c) Pielaszek Research, all rights reserved.
    The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
    In every case, proper references including Author(s) name(s) and URL of this webpage: must be provided.


Related papers
  1. Growth and EPR properties of NdVO4, HoVO4 and NdVO4 single crystals
  2. Surface charging of crystalline oxides in X-ray photoelectron spectroscopy - examples of LiNbO3 , Lu2SiO5 and LuVO4
  3. EPR and optical properties of PbMoO4:Co single crystals
  4. Temperature dependence of PL and EPR spectra of Sr0.33Ba0.67Nb2O6:Cr (0.02mol.%) single crystals
  5. Magnetic and optical properties of  Li0.28Na1.72Ge4O9:Cr, Mn (0.1mol%) single crystals
  6. High-pressure diffraction study of structural and elastic properties of zircon-type and scheelite-type RVO4 (R = Nd, Eu)
  7. Low-temperature structural properties of orthorhombic TbAlO3, TmAlO3 and LuAlO3 perovskites
  8. XRD, TEM, neutron diffraction and EPR characterization of LaCo1-yNiyO3 perovskites obtained from citrate precursors
  9. Lead Free Piezoceramics. A combined neutron diffraction and TEM-study on the system BNT–BT–KNN
  10. Growth and characterization of Li2B4O7 single crystals pure and doped with Co ions
  11. Temperature Raman scattering study of CaAl0.5Ta0.5O3 crystal
  12. Growth and Magnetic properties of rubidium rare earth double tungstates single crystals.
  13. Strain relaxation in thin films of LaSrCuO grown by pulsed laser deposition
  14. Origin of the negative thermal expansion in perovskite-type PrGaO3
  15. The effect of film-substrate mismatch on the properties of superconducting YBa2Cu3O7-δ films
  16. The enhancement of vortex pinning in ferromagnet-superconductor bilayers
  17. Transport and magnetic properties of La2/3Pb1/3MnO3 thin films
  18. Thermal expansion of NdGaO3 perovskite
  19. Crystal structure and thermal expansion of PrGaO3 in the temperature range 10-1253 K
  20. Twin structure of LSGMO crystals studied by Laue method

Presentation: Poster at 11th European Powder Diffraction Conference, Poster session, by Anatoliy Senyshyn
See On-line Journal of 11th European Powder Diffraction Conference

Submitted: 2008-05-01 00:02
Revised:   2009-06-07 00:48
© 1998-2022 pielaszek research, all rights reserved Powered by the Conference Engine