skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Structure and dielectric characterization of a new A-site deficient La{sub 5/3}MgTaO{sub 6} perovskite

Abstract

The crystal structure of new A-site deficient La{sub 5/3}MgTaO{sub 6} perovskite was investigated by neutron, X-ray and electron diffraction. Neutron and X-ray powder diffraction spectra were refined in the monoclinic I2/m space group, with the parameters of the unit cell a=5.6304(2)A, b=5.6226(2)A, c=7.9434(2)A and {beta}=90.04(1){sup o}. This structural model presumes a random distribution of the vacancies and takes into account both a rock salt-type Mg{sup 2+}/Ta{sup 5+} cation ordering and a{sup -}a{sup -}c{sup 0} configuration of the octahedral tilting. Electron diffraction showed that the crystal structure is more complex at the local level due to a short-range vacancy ordering. This observation in combination with the symmetry analysis leads to the conclusion that the C2/m symmetry with 2{radical}2a{sub p}x2{radical}2a{sub p}x2a{sub p} supercell is more adequate for the description of the crystal structure in the local level. Dielectric measurements performed in a wide frequency range were correlated with the crystal structure and compared with other ordered double perovskites. Far-infrared spectroscopy was used to characterize the lattice contribution to the dielectric response at the microwave frequencies. The complex dielectric function was evaluated and extrapolated down to the gigahertz range. The effect of the vacancies on the intrinsic dielectric losses is discussed based onmore » the spatial phonon correlation model.« less

Authors:
 [1];  [2];  [2];  [3];  [4];  [4];  [4]
  1. Department of Ceramics and Glass Engineering, CICECO, University of Aveiro, Aveiro 3810-193 (Portugal), E-mail: dkhalyavin@cv.ua.pt
  2. Department of Ceramics and Glass Engineering, CICECO, University of Aveiro, Aveiro 3810-193 (Portugal)
  3. Hahn-Meitner-Institut, Glienicker Strasse 100, Berlin D-14109 (Germany)
  4. Department of Physics, University of Minho, Braga 4710-057 (Portugal)
Publication Date:
OSTI Identifier:
21015616
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 180; Journal Issue: 1; Other Information: DOI: 10.1016/j.jssc.2006.09.016; PII: S0022-4596(06)00526-3; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ABSORPTION SPECTROSCOPY; DIELECTRIC MATERIALS; DIELECTRIC PROPERTIES; ELECTRON DIFFRACTION; FREQUENCY RANGE; INFRARED SPECTRA; LANTHANUM COMPOUNDS; MAGNESIUM COMPOUNDS; MAGNESIUM IONS; MICROWAVE RADIATION; MONOCLINIC LATTICES; NEUTRON DIFFRACTION; OXIDES; PEROVSKITE; SPACE GROUPS; STRUCTURAL MODELS; SYMMETRY; TANTALUM COMPOUNDS; TANTALUM IONS; VACANCIES; X-RAY DIFFRACTION

Citation Formats

Khalyavin, D.D., Senos, A.M.R., Mantas, P.Q., Argyriou, D.N., Tarroso Gomes, I., Vieira, L.G., and Ribeiro, J.L.. Structure and dielectric characterization of a new A-site deficient La{sub 5/3}MgTaO{sub 6} perovskite. United States: N. p., 2007. Web. doi:10.1016/j.jssc.2006.09.016.
Khalyavin, D.D., Senos, A.M.R., Mantas, P.Q., Argyriou, D.N., Tarroso Gomes, I., Vieira, L.G., & Ribeiro, J.L.. Structure and dielectric characterization of a new A-site deficient La{sub 5/3}MgTaO{sub 6} perovskite. United States. doi:10.1016/j.jssc.2006.09.016.
Khalyavin, D.D., Senos, A.M.R., Mantas, P.Q., Argyriou, D.N., Tarroso Gomes, I., Vieira, L.G., and Ribeiro, J.L.. Mon . "Structure and dielectric characterization of a new A-site deficient La{sub 5/3}MgTaO{sub 6} perovskite". United States. doi:10.1016/j.jssc.2006.09.016.
@article{osti_21015616,
title = {Structure and dielectric characterization of a new A-site deficient La{sub 5/3}MgTaO{sub 6} perovskite},
author = {Khalyavin, D.D. and Senos, A.M.R. and Mantas, P.Q. and Argyriou, D.N. and Tarroso Gomes, I. and Vieira, L.G. and Ribeiro, J.L.},
abstractNote = {The crystal structure of new A-site deficient La{sub 5/3}MgTaO{sub 6} perovskite was investigated by neutron, X-ray and electron diffraction. Neutron and X-ray powder diffraction spectra were refined in the monoclinic I2/m space group, with the parameters of the unit cell a=5.6304(2)A, b=5.6226(2)A, c=7.9434(2)A and {beta}=90.04(1){sup o}. This structural model presumes a random distribution of the vacancies and takes into account both a rock salt-type Mg{sup 2+}/Ta{sup 5+} cation ordering and a{sup -}a{sup -}c{sup 0} configuration of the octahedral tilting. Electron diffraction showed that the crystal structure is more complex at the local level due to a short-range vacancy ordering. This observation in combination with the symmetry analysis leads to the conclusion that the C2/m symmetry with 2{radical}2a{sub p}x2{radical}2a{sub p}x2a{sub p} supercell is more adequate for the description of the crystal structure in the local level. Dielectric measurements performed in a wide frequency range were correlated with the crystal structure and compared with other ordered double perovskites. Far-infrared spectroscopy was used to characterize the lattice contribution to the dielectric response at the microwave frequencies. The complex dielectric function was evaluated and extrapolated down to the gigahertz range. The effect of the vacancies on the intrinsic dielectric losses is discussed based on the spatial phonon correlation model.},
doi = {10.1016/j.jssc.2006.09.016},
journal = {Journal of Solid State Chemistry},
number = 1,
volume = 180,
place = {United States},
year = {Mon Jan 15 00:00:00 EST 2007},
month = {Mon Jan 15 00:00:00 EST 2007}
}