Structural analysis of lead magnesium niobate using synchrotron powder X-ray diffraction and the Rietveld method.
Acta Crystallogr B Struct Sci Cryst Eng Mater
; 72(Pt 3): 404-9, 2016 06 01.
Article
em En
| MEDLINE
| ID: mdl-27240772
ABSTRACT
The room-temperature synchrotron powder X-ray diffraction pattern of the single phase perovskite lead magnesium niobate (PMN) has shown significant broadening in the q range â¼â
5-7â
Å(-1) compared with standard LaB6 synchrotron powder X-ray diffraction data, taken under similar conditions. This broadening/asymmetry lies mainly towards the lower 2θ side of the Bragg peaks. Attempts to fit this data with the paraelectric cubic phase (Pm\bar 3m) and the local rhombohedral phase (R3m) corresponding to polar nanoregions (PNRs) are made using the Rietveld method. Rietveld refinements show that neither cubic (Pm\bar 3m) nor rhombohedral (R3m) symmetry can fit this XRD pattern satisfactorily. The two-phase refinement fits the experimental data satisfactorily and suggests that the weight percentage of the PNRs is approximately 12-16% at room temperature. The unit-cell volume of these rhombohedral PNRs is approximately 0.15% larger than that of the unit cell volume of the paraelectric cubic phase.
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Coleções:
01-internacional
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MEDLINE
Idioma:
En
Revista:
Acta Crystallogr B Struct Sci Cryst Eng Mater
Ano de publicação:
2016
Tipo de documento:
Article