Channeling analysis of the oxygen sublattices in oxide single crystals

Turos, A.; Meyer, O.; Nowicki, Ł.; Remmel, J.; Wieluński, M.

doi:10.1016/0168-583x(94)95862-9

Cited by 9 publications

(3 citation statements)

References 13 publications

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“…As a matter of fact the influence of positions of O atoms on the shape of U scans can be neglected for the specific case of uranium oxides. 64 This observation is in agreement with systematic small displacements of U atoms from fcc positions evidenced by x-ray, neutron, and electron diffraction analyses. 8,[20][21][22][23][24]29,30,[65][66][67][68][69][70][71][72][73][74][75][76][77][78][79] ͑ii͒ The channeling yield on U atoms in both investigated planes is largely enhanced with respect to UO 2 with typical values 0.40 and 0.45 for ͑001͒ and ͑110͒ planes, respectively.…”

Section: B Channeling Analysissupporting

confidence: 87%

“…38,64 As previously discussed in Sec. III, experimental U dips are much narrower in U 4 O 9−y than in UO 2 .…”

Section: Investigation Of the Uranium Sublatticementioning

confidence: 83%

“…38,64 Thus any significant disordering of the U sublattice would lead to a strong increase in the values of the minimum axial yields, a feature which is not observed experimentally. The channeling results lead us to conclude that the structure of U 4 O 9−y cannot be described by the presence of amorphous zones scattered in an unaltered UO 2 matrix.…”

Section: Investigation Of the Uranium Sublatticementioning

confidence: 91%

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Channeling investigation of the crystalline structure ofU4O9−y

2006

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The crystallographic structure of U 4 O 9−y crystals can be described in terms of a spatial arrangement of special aggregates of oxygen atoms distributed throughout the basic fluorite framework of UO 2 . The structure of U 4 O 9−y single crystals was investigated with the ion-channeling method by recording angular scans across major crystallographic directions and along major atomic planes. Monte Carlo simulations were performed to interpret the channeling data. The presence of various anionic clusters previously proposed ͑such as the Willis-type 2:2:2 aggregate and Bevan-type cuboctahedral cluster͒, as well as more recent models involving the incorporation of extra oxygen atoms as oxo groups forming uranyl-type bonds and a structural disordering of part of the uranium sublattice, were investigated. Channeling data exhibit satisfactory agreement with both the Willis and Bevan-type aggregates. They are incompatible with the presence of a glassy part in the uranium sublattice and indicate that the presence of uranyl-type bonds is unlikely.

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