science24.com - Crystal structure and thermal expansion of PrGaO3 in the temperature range 10-1253 K

Search for content and authors

Crystal structure and thermal expansion of PrGaO₃ in the temperature range 10-1253 K

Leonid Vasylechko ³, Anatoliy Senyshyn ³, Michael Knapp ², Marek Berkowski ⁴, Carsten Paulmann ¹, Ulrich Bismayer ¹, A. Matkovskii ³

1. University of Hamburg, Mineralogisch-Pertographisches Institut, Hamburg, Germany
2. Technische Universitat Darmstadt, Darmstadt, Germany
3. Lviv Polytechnic National University, 12 Bandera, Lviv 79013, Ukraine
4. Polish Academy of Sciences, Institute of Physics, al. Lotników 32/46, Warszawa 02-668, Poland

Abstract

Crystal structure and thermal expansion of PrGaO₃ have been investigated in the temperature range 10-1253 K by means of single crystal and high-resolution powder diffraction techniques using synchrotron radiation. Single crystal and powder diffraction experiments were carried out at the beamlines F1 and B2 at HASYLAB/DESY. PrGaO3 possesses an orthorhombically distorted GdFeO₃ type structure in the whole temperature range investigated. The changes in lattice parameters and cell volume are anisotropic and nonlinear with increasing temperature. Negative thermal expansion in [010]- and [100]-directions were detected in the temperature ranges 10-180 K and 10-50 K, respectively. Negative thermal volume expansion is observed in the temperature range 10-50 K. Due to pronounced anisotropy of the thermal expansion, the normalized values of the lattice parameters b_p and c_p become equal at 1200 K. For the average interatomic distances (PrO)₈-(PrO)₁₂, (GaO)₆ and (OO)₈ a linear increase with temperature is observed. For the temperature dependencies of the (PrPr)₆, (PrGa)₈ and (GaGa)₆ average distances a change of slope occurs at 200-300 K.
A Reduction of the bond-length distortion in the corresponding polyhedra with temperature and an increase of the values of the observed tolerance factors indicate a decrease of the perovskite structure deformation in PrGaO₃. From extrapolation of the experimental values of the interatomic distances and their ratios, the temperature of the predicted orthorhombic-to-rhombohedral phase transition could be estimated to 1840-1875 K.
Acknowledgement. This work was supported by WTZ (UKR-012-97), Ukrainian Ministry of Science (Project No. "Ion") and Polish Committee for Scientific Research (Grant N 7 T08A 00520).

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: https://science24.com/paper/635 must be provided.

Crystal structure and thermal expansion of PrGaO3 in the temperature range 10-1253 K

Presentation: poster at E-MRS Fall Meeting 2003, Symposium B, by Leonid Vasylechko See On-line Journal of E-MRS Fall Meeting 2003 Submitted: 2003-05-10 10:10 Revised: 2009-06-08 12:55

Crystal structure and thermal expansion of PrGaO₃ in the temperature range 10-1253 K

Presentation: poster at E-MRS Fall Meeting 2003, Symposium B, by Leonid Vasylechko
See On-line Journal of E-MRS Fall Meeting 2003

Submitted: 2003-05-10 10:10 Revised: 2009-06-08 12:55