Anomalous X-ray diffraction study of Pr-substituted BaCeO3â
-â
δ.
Acta Crystallogr B Struct Sci Cryst Eng Mater
; 71(Pt 4): 455-62, 2015 Aug.
Article
em En
| MEDLINE
| ID: mdl-26208626
The effect of Pr doping on the crystal structure and site occupancy was studied for the nominally synthesized BaCe1â
-â
xPrxO3â
-â
δ (x = 0, 0.2, 0.4, 0.6 and 0.8) perovskites using anomalous X-ray powder diffraction (AXRD) data and Rietveld analysis. Crystal structure parameters were accurately determined using 10,000â
eV photons, and the Pr occupancy was refined using data collected with 5962â
eV photons, close to the Prâ
LIII absorption edge. BaCe1â
-â
xPrxO3â
-â
δ crystallizes in the Pnma (No. 62) space group for all x values. Pr cations are mainly located at the Ce sites (perovskites B site), but a small fraction of them increasingly substitute some of the Ba ions at the A site as Pr content increases. The Pr doping introduces electronic defects (Pr(+3)/Pr(+4)) and oxygen vacancies needed for H2O incorporation and H-ionic conductivity. A decrease in the orthorhombic distortion would produce the opposite effects on the electronic and ionic mobility. The electronic mobility should increase due to an improvement in the overlap of the (Ce/Pr)4f-O2p orbital, while the proton mobility should decrease as a consequence of a larger hopping distance.
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1
Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Acta Crystallogr B Struct Sci Cryst Eng Mater
Ano de publicação:
2015
Tipo de documento:
Article
País de afiliação:
Argentina
País de publicação:
Reino Unido