Hostname: page-component-cd9895bd7-8ctnn Total loading time: 0 Render date: 2024-12-27T02:03:23.484Z Has data issue: false hasContentIssue false

Identification of the kinematical forbidden reflections from precession electron diffraction

Published online by Cambridge University Press:  31 January 2011

Jean-Paul Morniroli
Affiliation:
[email protected], Laboratoire de Métallurgie Physique et Génie des Matériaux, UMR CNRS 8517, Villeneuve d’Ascq, France
Gang Ji
Affiliation:
[email protected], Laboratoire de Métallurgie Physique et Génie des Matériaux, UMR CNRS 8517, Villeneuve d’Ascq, France
Get access

Abstract

The visibility of the kinematical forbidden reflections due to glide planes, screw axes and Wyckoff positions is considered both on experimental and theoretical electron precession patterns as a function of the precession angle. The forbidden reflections due to glide planes and screw axes become very weak and disappear at large precession angle so that they can be distinguished from the allowed reflections and used to deduce the space groups. Contrarily, those due to Wyckoff positions remain visible and strong provided they are located on a major systematic row. This difference of behavior between the forbidden reflections is confirmed by observation of the corresponding dark-field LACBED patterns and is interpreted using the Ewald sphere and the Laue circles from the availability of double diffraction paths. This study also proves that dynamical interactions remain strong along the main systematic rows present on precession patterns.

Type
Research Article
Copyright
Copyright © Materials Research Society 2009

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Morniroli, J.P. and Steeds, J.W., Ultramicroscopy 45, 219 (1992).Google Scholar
2. Gjønnes, J. and Moodie, A.F., Acta Cryst. 19, 65 (1965).Google Scholar
3. Steeds, J.W., Microscopia Elettronica in Trasmissione e Techniche di Analisi di Superficici nella Scienza dei Materiali, Editione Enea, Roma, 1986 Google Scholar
4. Vincent, R. and Midgley, P.A., Ultramicroscopy 53, 271 (1994).Google Scholar
5. Morniroli, J.P., Redjaïmia, A. and Nicolopoulos, S., Ultramicroscopy 107, 514 (2007).Google Scholar
6. Own, C.S., Marks, L.D. and Sinkler, W., Acta Cryst. A62, 434 (2006).Google Scholar
7. Morniroli, J.P., Electron Diffraction, http://www.univ-lille1.fr/lmpgm/Google Scholar
8. Stadelmann, P.A., Jems, http://cimewww.epfl.ch/people/stadelmann/jemsWebSite/jems.htmlGoogle Scholar
9. Morniroli, J.P., Microscopy and Microanalysis, 13, 126127 (2007)Google Scholar