MAGNETIC-PROPERTIES OF TETRAGONAL TBRU2GE2 AND TBRU2SI2

A detailed study of the magnetic properties of TbRu2Ge2 and TbRu2Si2 single crystals is presented, from specific heat and magnetization measurements. Both compounds exhibit very similar features, in particular a multistep metamagnetic behaviour at low temperature along the [001] easy direction, and the occurrence of a zero-field phase transition at a temperature far below the Neel temperature. The complex H-T magnetic phase diagrams are deduced, a situation typical of long-period commensurate or incommensurate systems.