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High-Resolution Electron Diffraction: Accounting for Radially and Angularly Invariant Distortions

Published online by Cambridge University Press:  08 May 2012

Daniel Carvalho
Affiliation:
Department of Materials Science and Metallurgical Engineering and Inorganic Chemistry, Materials Science and Engineering Group, Faculty of Sciences, University of Cádiz, 11510, Puerto Real, Cádiz, Spain
Francisco M. Morales*
Affiliation:
Department of Materials Science and Metallurgical Engineering and Inorganic Chemistry, Materials Science and Engineering Group, Faculty of Sciences, University of Cádiz, 11510, Puerto Real, Cádiz, Spain
*
Corresponding author. E-mail: [email protected]
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Abstract

The distortions present in an electron diffraction pattern can be classified into two categories: one is radially invariant and the other is angularly invariant. We report a method to compensate these displacements undergone by diffraction features promoted by any kind of artifacts generated in parallel beam electron diffraction conditions. This approach is not aimed at quantifying these distortions but only intends to aid in the measurement of lattice parameters of crystals with a significant increase of accuracy and precision as compared to previous approaches. It is based on statistical estimations of the relative positions between diffraction rings and/or spots after performing a transformation of the digitalized patterns to polar coordinates. The analytical method is based on fitting a Gaussian type profile to intensity distributions. This makes it possible to determine the lattice parameters of a polycrystal or single crystal with relative errors smaller than 0.1% for diffractograms acquired in photographic films and below 0.01% for those collected in imaging plates.

Type
Techniques Development
Copyright
Copyright © Microscopy Society of America 2012

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