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Title: Electron-doping through La{sup III}-for-Sr{sup II} substitution in (Sr{sub 1-} {sub x} La {sub x} ){sub 2}FeTaO{sub 6}: Effects on the valences and ordering of the B-site cations, Fe and Ta

Abstract

We have employed aliovalent A-site cation substitution, La{sup III}-for-Sr{sup II}, to dope the Sr(Fe{sub 0.5}Ta{sub 0.5})O{sub 3} perovskite oxide with electrons. Essentially single-phase samples of (Sr{sub 1-} {sub x} La {sub x} )(Fe{sub 0.5}Ta{sub 0.5})O{sub 3} were successfully synthesized up to x{approx}0.3 in a vacuum furnace at 1400 deg. C. The samples were found to crystallize (rather than with orthorhombic symmetry) in monoclinic space group P2{sub 1}/n that accounts for the partial ordering of the B-site cations, Fe and Ta. With increasing La-substitution level, x, the degree of Fe/Ta order was found to increase such that the La-richest compositions are best described by the B-site ordered double-perovskite formula (Sr,La){sub 2}FeTaO{sub 6}. From Fe L {sub 3} and Ta L {sub 3} XANES spectra it was revealed that upon electron doping the two B-site cations, Fe{sup III} and Ta{sup V}, are both prone to reduction. Magnetic susceptibility measurements showed spin-glass type behaviour for all the samples with a transition temperature slightly increasing with increasing x. -- Graphical abstract: Valence states of Fe and Ta are controlled in the partially ordered perovskite oxide (Sr,La){sub 2}FeTaO{sub 6}, through aliovalent La{sup III}-for-Sr{sup II} substitu0010ti.

Authors:
 [1];  [2];  [3];  [3];  [4];  [1];  [5]
  1. Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan)
  2. (Finland)
  3. Department of Chemistry and Center for Nano Storage Research, National Taiwan University, Taipei, (China)
  4. National Synchrotron Radiation Research Center, Hsinchu, (China)
  5. Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan). E-mail: karppinen@msl.titech.ac.jp
Publication Date:
OSTI Identifier:
20784838
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 179; Journal Issue: 1; Other Information: DOI: 10.1016/j.jssc.2005.10.004; PII: S0022-4596(05)00464-0; Copyright (c) 2005 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; CATIONS; IRON COMPOUNDS; LANTHANUM COMPOUNDS; MAGNETIC SUSCEPTIBILITY; MONOCLINIC LATTICES; ORTHORHOMBIC LATTICES; OXIDES; PEROVSKITE; SPACE GROUPS; SPIN GLASS STATE; STRONTIUM COMPOUNDS; TANTALUM COMPOUNDS; TRANSITION TEMPERATURE; VALENCE; X-RAY SPECTROSCOPY

Citation Formats

Rautama, E.-L., Laboratory of Inorganic and Analytical Chemistry, Helsinki University of Technology, FIN-02015 HUT, Chan, T.S., Liu, R.S., Chen, J.M., Yamauchi, H., and Karppinen, M.. Electron-doping through La{sup III}-for-Sr{sup II} substitution in (Sr{sub 1-} {sub x} La {sub x} ){sub 2}FeTaO{sub 6}: Effects on the valences and ordering of the B-site cations, Fe and Ta. United States: N. p., 2006. Web. doi:10.1016/j.jssc.2005.10.004.
Rautama, E.-L., Laboratory of Inorganic and Analytical Chemistry, Helsinki University of Technology, FIN-02015 HUT, Chan, T.S., Liu, R.S., Chen, J.M., Yamauchi, H., & Karppinen, M.. Electron-doping through La{sup III}-for-Sr{sup II} substitution in (Sr{sub 1-} {sub x} La {sub x} ){sub 2}FeTaO{sub 6}: Effects on the valences and ordering of the B-site cations, Fe and Ta. United States. doi:10.1016/j.jssc.2005.10.004.
Rautama, E.-L., Laboratory of Inorganic and Analytical Chemistry, Helsinki University of Technology, FIN-02015 HUT, Chan, T.S., Liu, R.S., Chen, J.M., Yamauchi, H., and Karppinen, M.. Sun . "Electron-doping through La{sup III}-for-Sr{sup II} substitution in (Sr{sub 1-} {sub x} La {sub x} ){sub 2}FeTaO{sub 6}: Effects on the valences and ordering of the B-site cations, Fe and Ta". United States. doi:10.1016/j.jssc.2005.10.004.
@article{osti_20784838,
title = {Electron-doping through La{sup III}-for-Sr{sup II} substitution in (Sr{sub 1-} {sub x} La {sub x} ){sub 2}FeTaO{sub 6}: Effects on the valences and ordering of the B-site cations, Fe and Ta},
author = {Rautama, E.-L. and Laboratory of Inorganic and Analytical Chemistry, Helsinki University of Technology, FIN-02015 HUT and Chan, T.S. and Liu, R.S. and Chen, J.M. and Yamauchi, H. and Karppinen, M.},
abstractNote = {We have employed aliovalent A-site cation substitution, La{sup III}-for-Sr{sup II}, to dope the Sr(Fe{sub 0.5}Ta{sub 0.5})O{sub 3} perovskite oxide with electrons. Essentially single-phase samples of (Sr{sub 1-} {sub x} La {sub x} )(Fe{sub 0.5}Ta{sub 0.5})O{sub 3} were successfully synthesized up to x{approx}0.3 in a vacuum furnace at 1400 deg. C. The samples were found to crystallize (rather than with orthorhombic symmetry) in monoclinic space group P2{sub 1}/n that accounts for the partial ordering of the B-site cations, Fe and Ta. With increasing La-substitution level, x, the degree of Fe/Ta order was found to increase such that the La-richest compositions are best described by the B-site ordered double-perovskite formula (Sr,La){sub 2}FeTaO{sub 6}. From Fe L {sub 3} and Ta L {sub 3} XANES spectra it was revealed that upon electron doping the two B-site cations, Fe{sup III} and Ta{sup V}, are both prone to reduction. Magnetic susceptibility measurements showed spin-glass type behaviour for all the samples with a transition temperature slightly increasing with increasing x. -- Graphical abstract: Valence states of Fe and Ta are controlled in the partially ordered perovskite oxide (Sr,La){sub 2}FeTaO{sub 6}, through aliovalent La{sup III}-for-Sr{sup II} substitu0010ti.},
doi = {10.1016/j.jssc.2005.10.004},
journal = {Journal of Solid State Chemistry},
number = 1,
volume = 179,
place = {United States},
year = {Sun Jan 15 00:00:00 EST 2006},
month = {Sun Jan 15 00:00:00 EST 2006}
}