Magnetic properties of lanthanide rhenium oxides Ln3ReO7 (Ln=Sm, Eu, Ho)

Ternary lanthanide rhenium oxides Ln3ReO7 (Ln=Sm, Eu, Ho) were prepared and their structures were determined by X-ray diffraction measurements. They crystallize in an orthorhombic superstructure of cubic fluorite (space group Cmcm for Ln=Sm, Eu; C2221 for Ln=Ho). The magnetic properties were characterized by magnetic susceptibility and specific heat measurements from 1.8 to 400 K. The Sm3ReO7 shows an antiferromagnetic transition at 1.9 K. The Eu3ReO7 indicates a magnetic anomaly at 12 K. On the other hand, the results of the specific heat measurements indicate that both Sm3ReO7 and Eu3ReO7 undergo a structure transition at 270 and 350 K, respectively. The Ho3ReO7 is paramagnetic down to 1.8 K.