Magnetostriction and structural distortion in rare-earth intermetallics

On the basis of the special symmetry of the rare-earth site in the Laves-phase cubic compounds RT₂ (R is a rare earth, T=Fe, Co, Ni) we predict the occurrence of a structural distortion which vanishes only when [100] is the easy magnetization direction. An extraordinary external strain accompanies the distortion and provides an explanation of the observed size and anisotropy of the magnetostriction in RFe₂.