X-ray structure refinements and strain analysis of substituted cubic lead pyrochlores Pb2(M2-yPby)O7-δ(0.0<y<0.8; M=Nb or Ta)

Nalini, G. ; Somashekar, R. ; Guru Row, T. N. (2001) X-ray structure refinements and strain analysis of substituted cubic lead pyrochlores Pb2(M2-yPby)O7-δ(0.0<y<0.8; M=Nb or Ta) Journal of Solid State Chemistry, 156 (1). pp. 207-212. ISSN 0022-4596

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Official URL: http://linkinghub.elsevier.com/retrieve/pii/S00224...

Related URL: http://dx.doi.org/10.1006/jssc.2000.8983

Abstract

The phase diagrams in the PbO-Nb2O5 system and the PbO-Ta2O5 system depict pyrochlore structure at certain molar ratios. Compositions Pb2Nb1.51Pb0.49O6.30 (1), Pb2Ta1.4Pb0.6O6.21 (2), and Pb2Ta1.25Pb0.75O6.57 (3) belonging to this family, are refined in the cubic space group Fd3-m (Z=8; lattice parameter a=10.762(1), 10.744(1), 10.757(5) Å, respectively) using the Rietveld refinement approach. The analyses suggest that the B-site is partially occupied by Pb leading to the general formula Pb2(M2-yPby)O7-δ (0.0<y<0.8; M=Nb or Ta). There is an overall broadening observed in the X-ray peak widths in 1, 2, and 3 compared to the Pb-deficient parent phases. It is observed that the X-ray peak widths of 2 is broad, while 3 displays narrow peak widths. It is found via strain analysis that the line broadening observed correlates with the strain in the lattice.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
Keywords:Pyrochlore; Rietveld Refinement; Strain Analysis; Lead Niobates; Lead Tantalates
ID Code:11850
Deposited On:13 Nov 2010 13:47
Last Modified:03 Jun 2011 04:25

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