Changes of the local oxygen content and ordering at twin boundaries of hi superconductors

We demonstrate here the way the local oxygen content and configuration in (Formula presented)(Formula presented)(Formula presented) can be related to specific Fourier components of the image intensity in experimental high resolution electron microscopy images along the [001] zone axis. We further show that this allows us to evaluate experimentally local changes in the oxygen content and ordering at unit cell resolution in projection across twin boundaries in a high-(Formula presented)(Formula presented)(Formula presented) superconductor which exhibited (Formula presented)=92 K. Our studies indicate that, on traversing a twin boundary, there is not only an ordering change but also a reduction in the oxygen content.