Synthesis and structural analysis of Bi2-ySryIr2O7, a new pyrochlore solid solution
Por:
Cosio-Castaneda, C, De La Mora, P, Tavizon, G
Publicada:
1 may 2011
Resumen:
This paper presents a study of the synthesis and structural properties of the new pyrochlore-type Bi2-ySryIr2O7 series. Ten compositions with 0.0 <= y <= 0.9 were prepared by solid-state reaction with thermal treatments at 873, 1073 and 1323 K under atmospheric pressure conditions. Structural refinements from X-ray powder diffraction data by the Rietveld method show that all compounds of the Bi2-ySryIr2O7 solid solution crystallize in a alpha-pyrochlore structure. The main structural difference when bismuth is substituted by strontium concerns the x position of the O1 (x, (1)/(8), (1)/(8)). This substitution significantly increases the Bi/Sr-O1 distance and diminishes the Ir-O1 distance; this implies that the Ir-O1-Ir bond angle increases. With the Sr substitution, the IrO6 local configuration goes from a flattened trigonal antiprism, y < 0.5, to an elongated one, y > 0.5, passing through an octahedral array, y similar to 0.5. The electrical consequences of these structural changes obs
Filiaciones:
Cosio-Castaneda, C:
Univ Nacl Autonoma Mexico, Fac Quim, Dept Fis & Quim Teor, Mexico City 04510, DF, Mexico
De La Mora, P:
Univ Nacl Autonoma Mexico, Fac Ciencias, Dept Fis, Mexico City 04510, DF, Mexico
Tavizon, G:
Univ Nacl Autonoma Mexico, Fac Quim, Dept Fis & Quim Teor, Mexico City 04510, DF, Mexico
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