Rhombohedral distortion in highly magnetostrictive Laves phase compounds

A model is presented which produces a magnetostrictively driven rhombohedral distortion (λ111) in cubic diamond‐like structures. No tetragonal magnetostrictive distortion (λ100) is allowed, which is consistent with the experimental observation, λ111≫λ100. From x‐ray and single crystal measurements we find ‖λ111/λ100‖≳600 for DyFe2. Rhombohedral distortions (λ111) are examined in the ternary Tb1−xGexFe2, Tb1−xYxFe2 and Tb1−xDyxFe2 systems by x‐ray methods. The single‐ion nature of the giant Tb magnetostriction in TbFe2 is verified.