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CBED and LACBED: characterization of antiphase boundaries
J P Morniroli1, M L Nó, P P Rodríguez
1UMR CNRS 8517, Université des Sciences et Technologies de Lille et Ecole Nationale Supérieure de Chimie de Lille, Cité Scientifique, 59655 d'Ascq Cédex, Villeneuve, France. jean-paul.morniroli@univ.lille.fr
Ultramicroscopy
|November 12, 2003
Summary
Convergent-beam electron diffraction (CBED) and large-angle convergent-beam electron diffraction (LACBED) can now characterize antiphase boundaries (APBs). These techniques reveal APBs by splitting superlattice excess lines in diffraction patterns.
Area of Science:
- Materials Science
- Crystallography
- Solid State Physics
Background:
- Convergent-beam electron diffraction (CBED) and large-angle convergent-beam electron diffraction (LACBED) are established techniques for analyzing crystal defects.
- Previous applications include the characterization of dislocations, grain boundaries, and stacking faults.
Purpose of the Study:
- To investigate the application of CBED and LACBED for characterizing antiphase boundaries (APBs), a significant defect in materials science.
- To theoretically predict and experimentally verify the effects of APBs on CBED and LACBED patterns.
Main Methods:
- Theoretical analysis of how antiphase boundaries influence CBED and LACBED patterns.
- Experimental validation using specimens with known antiphase boundaries.
- Development of methods for identifying unknown APBs.
Main Results:
- Antiphase boundaries cause superlattice excess lines in CBED and LACBED patterns to split into two equally intense lines when the electron beam is incident on the boundary.
- Experimental results confirm the theoretical predictions for different types of APBs.
Conclusions:
- CBED and LACBED are effective methods for characterizing antiphase boundaries.
- The splitting of superlattice excess lines serves as a clear indicator of APBs.
- The study discusses the advantages and limitations of both techniques for APB analysis.