Change of diffusion mechanism with lattice parameter in the series of lanthanide indides having L12 structure

Using perturbed angular correlation spectroscopy, jump frequencies of Cd tracer atoms were measured for 12 indides In3(B) (B = rare earth) in paired samples having compositions at each of the opposing phase boundaries. Jump frequencies in heavy lanthanide indides were observed to be smaller for In-richer compositions than for In-poorer compositions, but greater in the light lanthanide indides. These findings signal an unmistakable change in diffusion mechanism from the simple In-sublattice vacancy mechanism for heavy lanthanides to a B-vacancy mechanism for light lanthanides.