Order-disorder transition in Nd{sub 2-y}Gd{sub y}Zr{sub 2}O{sub 7} pyrochlore solid solution: An X-ray diffraction and Raman spectroscopic study

Journal Article · Mon Oct 15 04:00:00 EDT 2007 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2007.07.007· OSTI ID:21049493

Mandal, B P ^[1]; Banerji, Ankita ^[2]; Sathe, Vasant ^[3]; Deb, S K ^[2]

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1. Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)
2. High Pressure Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)
3. UGC-DAE CSR, University Campus, Khandwa Road, Indore 452 017 (India)

Powder X-ray diffraction (XRD) and Raman spectroscopic study of order-disorder-phase transition with increase in the content of Gd in Nd{sub 2-y}Gd{sub y}Zr{sub 2}O{sub 7} solid solution is being reported. It has been observed from Rietveld analysis that with increase in concentration of Gd in Nd{sub 2-y}Gd{sub y}Zr{sub 2}O{sub 7}, the value of the x parameter of the 48f oxygen changes from 0.332(1) to 0.343(1) with a sudden change in the slope for y=1.8, which indicates that the structure is transforming from ordered pyrochlore to disordered pyrochlore. In addition to that a sudden and drastic change in the Raman spectra including changes in the position and width of several Raman modes beyond y{>=}1.8 has also been observed which has been correlated with increasing disorder. Based on these studies, it is suggested that there is a discontinuous order-disorder transition from 'perfect pyrochlore' to 'defect pyrochlore' phase in Nd{sub 2-y}Gd{sub y}Zr{sub 2}O{sub 7} solid solution. - Graphical abstract: Raman spectra of Nd{sub 2-y}Gd{sub y}Zr{sub 2}O{sub 7} with increasing proportion of Gd in Nd{sub 2-y}Gd{sub y}Zr{sub 2}O{sub 7} series. A transition from ordered pyrochlore to disordered pyrochlore can be seen at y{approx}1.8.

• OSTI ID: 21049493
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 10 Vol. 180; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
CERAMICS
GADOLINIUM COMPOUNDS
NEODYMIUM COMPOUNDS
ORDER-DISORDER TRANSFORMATIONS
OXIDES
PYROCHLORE
RAMAN SPECTRA
RAMAN SPECTROSCOPY
SOLID SOLUTIONS
X-RAY DIFFRACTION
ZIRCONIUM COMPOUNDS