Electronic Resource
[S.l.]
:
International Union of Crystallography (IUCr)
Acta crystallographica
38 (1982), S. 310-317
ISSN:
1600-5724
Source:
Crystallography Journals Online : IUCR Backfile Archive 1948-2001
Topics:
Chemistry and Pharmacology
,
Geosciences
,
Physics
Notes:
The image formation of high-voltage, high-resolution electron microscopy of ordered alloys has been studied on the basis of many-beam dynamical diffraction theory. It is revealed that superstructure images are observable for a rather thick crystal when nearly kinematical relationships hold among certain beams of the superlattice reflections; these beams are almost in phase and have amplitudes proportional to their structure factors. Thickness dependences of the phase differences and the scattering amplitudes are calculated for the superstructure of D023 type of the gold-based alloys Au3X (X = Mg, Zn and Cd). The results are discussed in connection with the difference in atomic scattering factors of the constituents X. The contrast of the superstructure image is discussed in terms of the amplitude-phase diagram of the superlattice reflections.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1107/S0567739482000679
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