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Superscrew dislocation contrast on synchrotron white‐beam topographs: an accurate description of the direct dislocation image
Author(s) -
Huang X. R.,
Dudley M.,
Vetter W. M.,
Huang W.,
Si W.,
Carter Jr C. H.
Publication year - 1999
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889899002939
Subject(s) - synchrotron , dislocation , materials science , diffraction , optics , diffraction topography , synchrotron radiation , contrast (vision) , beam (structure) , crystallography , x ray crystallography , physics , chemistry , composite material
A kinematic (geometrical) diffraction simulation model has been developed to provide understanding of direct dislocation images on synchrotron white‐beam X‐ray topographs, and has been successfully applied to illustrate the contrast formation mechanisms involved in images of micropipe‐related superscrew dislocations in silicon carbide crystals. The coincidence of the simulations with the contrast features of the superscrew dislocation images, recorded using a series of synchrotron topography techniques, shows that this model is capable of revealing the detailed diffraction behavior of the highly distorted region around the dislocation core and determining the quantitative characteristics of the dislocations. The simulation technique is thus demonstrated to be a simple but efficient method for interpretation of synchrotron topographs, and may be applied to explain the topographic contrast characters of general crystal defects.