Magnetostriction in the mixed magnetic compound TbRu2Ge2

Abstract Magnetostriction measurements performed on the tetragonal TbRu 2 Ge 2 compound at a low temperature are presented. At 2.9 K, the curves exhibit a spectacular metamagnetic behaviour similar to that observed on the magnetization curves, due to the successive changes of long-period commensurate antiferromagnetic structure. The mixed character of these structures (alternance of high- and low-moment Tb ions) does not give rise to specific features. Consequences on the magnetoelastic couplings are discussed.