Abstract
THE X-ray method of estimating the layer diameter in samples of graphite, based on the breadths of the hk0 reflexions, leads to apparent diameters of a few hundred Å, On the other hand, electron micrographs of the same sample show flakes the dimensions of which are some thousands of Å, nearly an order of magnitude larger. The discrepancy could arise from the simultaneous occurrence of strain broadening and particle-size broadening, or from the ‘tangent-plane approximation’1,2 being insufficiently good. The only hk0 reflexion which can readily be examined is 11&2macr;0, and measurements of integral breadths or half-widths require two reflexions in order to separate strain broadening and particle-size broadening. Measurement of the variance of a line profile, on the other hand, can in principle separate the two effects even when only one line is available for examination3. Use of the variance also makes it possible to allow for some departure from the conditions within which the tangent-plane approximation is valid.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Patterson, A. L., Phys. Rev., 56, 972 (1939).
Wilson, A. J. C., X-ray Optics, 38 (London: Methuen, 1962).
Wilson, A. J. C., Proc. Phys. Soc., 81, 41 (1963).
Warren, B. E., Phys. Rev., 59, 693 (1941).
Wilson, A. J. C., Acta Crystallograph., 2, 245 (1949).
Bacon, G. E., Acta Crystallograph., 7, 359 (1954).
Wilson, A. J. C., Proc. Phys. Soc., 80, 286 (1962).
Langford, J. I., and Wilson, A. J. C., in Crystallography and Crystal Perfection, edit. by Ramachandran, G. N., 207 (London: Academic Press, 1963).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
EELES, W., WILSON, A. Layer Diameter in Graphite. Nature 205, 66 (1965). https://doi.org/10.1038/205066a0
Published:
Issue Date:
DOI: https://doi.org/10.1038/205066a0
- Springer Nature Limited