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Quantitative Convergent Beam Electron Diffraction (CBED) Measurements of Low-Order Structure Factors in Nickel

Published online by Cambridge University Press:  02 July 2020

M. Saunders ,
A. G. Fox  and
P. A. Midgley
M. Saunders
Affiliation:
Center for Mat. Sci., Dept. of Mech. Eng., Naval Postgraduate School, Monterey, CA93943.
A. G. Fox
Affiliation:
Center for Mat. Sci., Dept. of Mech. Eng., Naval Postgraduate School, Monterey, CA93943.
P. A. Midgley
Affiliation:
H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol, UK.
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Extract

The introduction of quantitative CBED techniques in recent years has led to experimental studies of charge densities in crystalline materials with unprecedented accuracy. Despite these successes, the development process is still on-going with the aim of gaining a better understanding of the techniques. With this in mind, we have undertaken a systematic study of the low-order structure factors of nickel using the ZAPMATCH zone-axis pattern matching technique of Bird and Saunders. In this approach, a set of low-order structure factors (both elastic and absorptive components) is adjusted until a best-fit is obtained between a many-beam simulation and an elastic filtered zone-axis pattern. Additional higher-order structure factors are included to converge the scattering potential but are kept fixed at neutral atom values during the fit. The questions we set out to address are (i) how to choose the correct number of structure factors to refine from a given data-set, (ii) are the absorptive structure factor components we refine of any use, and (iii) can we determine Debye-Waller factors at the same time as we measure the charge density? The first two points are discussed here.

Type
Analytical Electron Microscopy
Information
Microscopy and Microanalysis , Volume 3 , Issue S2: Proceedings: Microscopy & Microanalysis '97, Microscopy Society of America 55th Annual Meeting, Microbeam Analysis Society 31st Annual Meeting, Histochemical Society 48th Annual Meeting, Cleveland, Ohio, August 10-14, 1997 , August 1997 , pp. 1013 - 1014
Copyright
Copyright © Microscopy Society of America 1997

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References

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