Crystallographic, magnetic and electrical characteristics of R^sub 3^Ni^sub 8^Sn^sub 4^ compounds (R = Y, Nd, Sm, Gd, and Tb)

The R3Ni8Sn4 compounds (R = Y, Nd, Sm, Gd, and Tb) have been synthesized and studied by powder X-ray diffraction, magnetic and electrical properties measurements. They crystallize in Lu3Co7.77Sn4 structure type (space group P63mc), and are characterized by different occupancy of some atomic positions, giving 3:8:4 stoichiometry in one case or statistical mixture of Ni and Sn in the other. The magnetic properties were studied in the temperature range 2-300 K and showed that at low temperatures Gd3Ni8Sn4 and Tb3Ni8Sn4 compounds exhibit ferromagnetic and antiferromagnetic ordering, respectively, while at higher temperatures both stannides are Curie-Weiss paramagnets. The Y3Ni8Sn4 stannide is a Pauli paramagnet while in Sm3Ni8Sn4 the magnetism is weak in the temperature range 2-300 K. The electrical properties of the R3Ni8Sn4 compounds showed metallic type of conductivity. The performed electronic structure calculations of Y3Ni8Sn4 are in a good agreement with electrical and magnetic studies.