Jianguo Deng

Rare-earth transition-metal chalcogenides Ln{sub 3}MGaS{sub 7} (Ln=Nd, Sm, Dy, Er; M=Co, Ni) and Ln{sub 3}MGaSe{sub 7} (Ln=Nd, Sm, Gd, Dy, M=Co; Ln=Nd, Gd, Dy, M=Ni)

Abstract Fifteen new rare-earth transition-metal chalcogenides, Ln 3 M GaS 7 ( Ln =Nd, Sm, Dy, Er; M =Co, Ni) and Ln 3 M GaSe 7 ( Ln =Nd, Sm, Gd, Dy, M =Co; Ln =Nd, Gd, Dy, M =Ni), have been synthesized by solid state reactions. They are isostructural, adopt Ce 3 Al 1.67 S 7 —related structure type, and crystallize in the non-centrosymmetric hexagonal space group P 6 3 . They adopt a three-dimensional framework composed of LnQ 7 monocapped trigonal prisms with the interesting [ MQ 3 ] 4− chains and isolated Ga Q 4 tetrahedra lying in two sets of channels in the framework. The magnetic susceptibility measurements on Ln 3 CoGa Q 7 ( Ln =Dy, Er, Q =S; Ln =Dy, Q =Se) indicate that they are paramagnetic and obey the Curie–Weiss law over the entire experimental temperature, while the magnetic susceptibility of Sm 3 CoGaSe 7 deviates from the Curie–Weiss law as a result of the crystal field splitting.