ISSN:
1600-5775
Source:
Crystallography Journals Online : IUCR Backfile Archive 1948-2001
Topics:
Geosciences
,
Physics
Notes:
Crystal structures of (Ba1−xLax)2In2O5+x (x=0.00, 0.20, 0.30, 0.40, 0.50) were analyzed by EXAFS and the powder X-ray Rietveld method. A Fourier transform of In K-edge EXAFS data from (Ba1−xLax)2In2O5+x showed a peak between 1.2 and 2.0 Å attributed to the nearest oxide ions around In3+ cation. The peak was back-Fourier transformed, and the structural parameters were refined by the least square fitting. The coordination number of In3+ cation increases with increasing La3+ cation content. This means oxygen is introduced at interstitial site by keeping an electroneutrality. As a result of the oxygen distribution, the oxide ion vacancies distribute randomly. The electrical conductivities of (Ba1−xLax)2In2O5 rapidly increased above 1203 K due to the order–disorder transition of oxygen vacancy. On the other hand, the electrical conductivities of (Ba1−xLax)2In2O5+x (x=0.20, 0.30, 0.35, 0.40, 0.45, 0.50) did not show the sharp discontinuity in the conductivity because the disorder phase of defective perovskite type structure was stabilized by doping La3+ cations at A-site even at low temperature.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1107/S090904950002094X
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