Crystal structure and magnetic properties of novel Hf3Ni2Si3-type R3Co2Ge3 compounds (R=Y, Sm, Tb-Tm)

► The {Y, Sm, Gd-Tm}3Co2Ge3 adopts the Hf3Ni2Si3-type structure (space group Cmcm). ► They demonstrate complex field sensitive antiferromagnetic ordering. ► The 4d site rare earth sublattice plays crucial role in the magnetism of R3Co2Ge3.