Crystal structure and magnetic properties of R3Mn0.5GeS7 (RÂ =Â Y, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho and Er)

The crystal structures of quaternary R3Mn0.5GeS7 (R = Y, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho and Er) compounds of La3Mn0.5SiS7 structure type (space group P63, Pearson symbol hP23) were determined by means of single crystal X-ray diffraction. The R atoms occupy trigonal prisms with two additional atoms, the Mn atoms are located in octahedra, while the Ge atoms are located in tetrahedra. Magnetic studies were performed on polycrystalline samples of Y3Mn0.5GeS7, Pr3Mn0.5GeS7 and Dy3Mn0.5GeS7. The former compound is a Curie-Weiss paramagnet due to magnetic moments carried on trivalent Mn ions. The other ones exhibit localized paramagnetic behavior due to both Mn3+ and R3+ sublattices. While the Dy-bearing sulfide orders antiferromagnetically below 5.5 K, no unambiguous indication of any magnetic ordering in Y3Mn0.5GeS7 and Pr3Mn0.5GeS7 was found down to 1.72 K.