Answers are grounded in this paper and cite their sources.
The ordered structure of at 70 - 75 K has been studied by time-resolved neutron powder diffraction. The ordered superlattice has a structure with approximately four full D sites and one vacant D site in successive (420) planes, which is consistent with previous observations. Several superlattice lines not reported in previous single-crystal studies were observed. Quantitative information about the ordered structure was obtained by careful Rietveld analysis of the data, including anisotropic line broadening and diffuse peak background corrections. The structure refinement confirms a relaxation of D atoms towards the vacant planes and reveals a related second-order displacement of the D atoms in the octahedral sites towards a preferred vacant nearest-neighbour site. The thermal vibration along the c-axis is anisotropic as a result of the preferential relaxation.
No takes yet. Share an insight, caveat, or question.
Wu et al. (1996) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: