It was shown how the local O content and configuration in this material could be related to specific Fourier components of the image intensity in experimental high-resolution electron microscopic images along the [001] zone axis. It was also shown that this permitted the experimental evaluation of local changes in the O content and ordering, at unit-cell resolution, across twin boundaries. The results indicated that, upon traversing a twin boundary, there was not only an ordering change but also a reduction in the O content.

Y.Yan, W.Y.Liang, T.Walther, W.M.Stobbs: Physical Review B, 1996, 54[22], 16234-7