An X-ray Investigation of Thermal Mean-Square Atomic Displacements in Magnesium, Cadmium and Mg3Cd
- 1 June 1971
- journal article
- Published by IOP Publishing in Japanese Journal of Applied Physics
- Vol. 10 (6) , 786-793
- https://doi.org/10.1143/jjap.10.786
Abstract
Measurements have been made of integrated intensities of X-ray symmetrical reflections from single crystals of magnesium, cadmium and Mg3Cd, kept at temperatures ranging from room temperature to about 90°K. It is observed that the thermal mean-square atomic displacements along two directions, the one parallel to the hexagonal c-axis \overlineu z 2 and the other perpendicular to the c-axis \overlineu x 2, are nearly the same in Mg3Cd, showing little anisotropy. The result suggests that thermal vibrational amplitudes in the alloy can not be a simple average of those in magnesium and cadmium. No appreciable difference is observed between the mean-square displacements of an ordered and an imperfectly ordered Mg3Cd. The mean-square atomic displacements is calculated for magnesium and cadmium applying Zener's theory of thermal vibration in hexagonal crystals and is compared with the observed displacements. Discussions are given on the correlation between \overlineu z 2/\overlineu x 2 and the axial ratio, c/a, of hexagonal close-packed metals and also on the the thermal mean-square displacements in alloys.Keywords
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