Structured Diffuse Scattering as an Indicator of Inherent Cristobalite-like Displacive Flexibility in the Rare Earth Zirconate Pyrochlore LaδZr1−δO2−δ/2, 0.49<δ<0.51
✍ Scribed by Yasunori Tabira; Ray Withers; John Thompson; Siegbert Schmid
- Publisher
- Elsevier Science
- Year
- 1999
- Tongue
- English
- Weight
- 322 KB
- Volume
- 142
- Category
- Article
- ISSN
- 0022-4596
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✦ Synopsis
A detailed electron and X-ray powder diffraction study has been made of the compositional and displacive flexibility of the rare earth zirconate pyrochlore (1؊ )ZrO 2 • LaO 1.5 ؍ (La 3؉ ) (Zr 4؉ ) 1؊ O 2؊ /2 , &0.5. The extent of the pyrochlore ''solid solution'' in specimens rapidly quenched from 1500°°C is shown to be considerably narrower than previously reported and certainly less than 2 mol.% in width. A weak but highly structured and quite reproducible diffuse intensity distribution in the form of {110}* polarized sheets of diffuse intensity perpendicular to each of the six 11102 real space directions is observed in electron diffraction patterns and interpreted in terms of -cristobalite-like 11102 tetrahedral edge rotation of essentially rigid O(2)(La) 4 tetrahedra.