Composition Dependence of the Long-Period Layer Stacking Sequence in the Structure of the Ternary Alloy Mg₃In_1−xCd_x

Abstract

The effect of the replacement of some fraction of the indium atoms with cadmium atoms on the structural stability of the long-period layer stacking sequence in Mg₃In has been studied by means of X-ray and electron diffraction experiments. The observed changes in electron diffraction patterns can be described by Kakinoki’s equation and suggest that when the cadmium content is increased the stacking sequence changes from (31)₃ to (11), passing through (3111)₃, with increasing amount of stacking disorder, while the atomic arrangement in the close-packed plane remains unchanged irrespective of the composition. Structural changes observed in the present investigation have been found similar to the pressure effects in Mg₃In previously reported. The stability of the long-period layer stacking structure is briefly discussed by application of the pseudo-potential theory.