Crystal-structure effects in the Ce<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="italic">L</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>-edge x-ray-absorption spectrum of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">CeO</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow

Soldatov, A. V.; Ivanchenko, T. S.; Longa, Stefano Della; Kotani, Akio; Iwamoto, Yoshitake; Bianconi, A.

doi:10.1103/physrevb.50.5074

Cited by 210 publications

(152 citation statements)

References 32 publications

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“…The intense peaks B and C can be interpreted as transitions toward O 2p state hybridized with Ce ͑or dopant͒ 5d-e g and 5d-t 2g states that are split under the crystalfield effects. 25,26 Therefore, the relative intensity of peaks B and C is sensitive to the change in crystal structure. Particularly, in nonstoichiometric oxides, it has been suggested that the enhancement of peak B could be introduced by the local ordering of oxygen vacancies.…”

Section: Resultsmentioning

confidence: 99%

Oxygen-vacancy ordering in lanthanide-doped ceria: Dopant-type dependence and structure model

et al. 2008

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Studies of electron energy loss spectroscopy and selected area electron diffraction ͑SAED͒ were systematically performed on 15 and 25 at. % lanthanide ͑Ln͒-doped ceria samples ͑Ln= Sm, Gd, Dy, and Yb͒, through which the local ordering of oxygen vacancies that develops with increase in doping level was confirmed in the sequence of ͑Gd, Sm͒ Ͼ DyϾ Yb. Furthermore, a monotone correlation between the development of the ordering and the degradation of ionic conductivity with increasing the doping concentration from 15 to 25 at. % was observed. Based on the analysis of SAED patterns, a structural model for the ordering of oxygen vacancies has been constructed, in which the arrangement of oxygen vacancies is similar to that in C-type Ln 2 O 3 oxides and the 1 2 ͗110͘ pairs of the vacancies are preferred. Then, the factors that can influence the formation of the ordering are discussed.

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Section: Resultsmentioning

confidence: 99%

Oxygen-vacancy ordering in lanthanide-doped ceria: Dopant-type dependence and structure model

et al. 2008

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“…Among these characteristics, peak A is obvious in pure ceria but weaker in doped ceria, which could be explained by the decrease of Ce concentration in doped ceria since this preedge peak is related to the hybridization between oxygen and Ce 4+ cations. 15,16 Inversely, the relative intensity of peak B in doped ceria is considerably higher than that of pure ceria. Previous studies had shown that the intensities of peaks B and C can be influenced by the crystal structure 16,17 and particularly, the enhancement of peak B could be introduced by the ordering of oxygen vacancies in nonstoichiometric oxides.…”

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confidence: 99%

“…15,16 Inversely, the relative intensity of peak B in doped ceria is considerably higher than that of pure ceria. Previous studies had shown that the intensities of peaks B and C can be influenced by the crystal structure 16,17 and particularly, the enhancement of peak B could be introduced by the ordering of oxygen vacancies in nonstoichiometric oxides. 14 In our samples, the increase in peak B is different with a sequence of SmϾ DyϾ Y Ͼ Yb, which agrees with the extra diffraction spots on SAED patterns ͑Fig.…”

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confidence: 99%

“…Here we used pure ceria as a standard sample for comparison since the calculated value of I B / I C for pure ceria ͑ϳ0.65͒ is very close to the ratio of 2 / 3 for CeO 2 with an ideal fluorite structure ͑calculated from the band density of states͒. 16 Table I displays both the value of ⌬͑I B / I C ͒ and the conductivity of doped ceria measured at 500°C ͑in air͒ by the dc threeprobe method. As the doping concentration becomes 15 at.…”

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Oxygen vacancy ordering in heavily rare-earth-doped ceria

Mori

et al. 2006

Applied Physics Letters

122

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25 at. % Rare-earth (RE)-doped ceria samples (RE=Sm, Dy, Y, and Yb) were examined using transmission electron microscopy and electron energy loss spectroscopy, from which the oxygen vacancy ordering in nanosized domains was confirmed. The relationships of the dopant type, oxygen vacancy ordering, and ionic conductivity of doped ceria were established. It is found that the ordering of oxygen vacancies depends strongly on the dopant type, and the development of nanosized domains with a higher degree of ordering can lead to a more dramatic decrease of ionic conductivity in doped ceria.

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“…Peak A results from the hybridization between oxygen and Ce 4+ cations, 30,31 which is obvious in pure ceria and becomes weak in doped ceria because of the decrease of the Ce concentration in doped ceria. As for the case of peaks B and C, previous studies have shown that the relative intensities of the peaks can be influenced by the crystal structure 30,31 and the enhancement of peak B could be due to the ordering of oxygen vacancies in nonstoichiometric oxides. 19,29 To compare the relative intensities of peaks B and C, the spectra in Fig.…”

Section: B Ordering Of Oxygen Vacancies In the Domainsmentioning

confidence: 99%

Compositional and valent state inhomogeneities and ordering of oxygen vacancies in terbium-doped ceria

Mori

et al. 2007

Journal of Applied Physics

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Intragranular distributions of composition and valent state in sintered Tb-doped ceria have been systematically investigated. Through detailed studies of electron energy loss spectroscopy and energy filtering transmission electron microscopy, both compositional and valent state inhomogeneities of Ce and Tb were confirmed, which are related to the existence of nanosized domains in Tb-doped ceria. Compared with their matrix, the domains have higher Tb concentration and Ce and Tb cations in the domains tend to be trivalent. Furthermore, ordering of oxygen vacancies in the domains, which increases with increasing doping concentration, has been determined by EELS.

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Crystal-structure effects in the CeL3-edge x-ray-absorption spectrum ofCeO2

Cited by 210 publications

References 32 publications

Oxygen-vacancy ordering in lanthanide-doped ceria: Dopant-type dependence and structure model

Oxygen-vacancy ordering in lanthanide-doped ceria: Dopant-type dependence and structure model

Oxygen vacancy ordering in heavily rare-earth-doped ceria

Compositional and valent state inhomogeneities and ordering of oxygen vacancies in terbium-doped ceria

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