Electrical and magnetic properties of new mixed transition metal sulfides BaKCu3MS4 (M = Mn, Co, Ni)

New transition metal sulfides BaKCu3MS4 (M = Mn, Co, Ni) were prepared from BaCO3, K2CO3, and the corresponding transition metal oxides by CS2/Ar sulf urization. The materials are based on a common structural pattern consistin g of 2-D arrangements of MS4 tetrahedra linked by edges, crystallizing in t he tetragonal ThCr2Si2-type structure in space group I4/mmm. Electrical res istivity measurements show that the new phases are semiconducting. The temp erature dependence of magnetic susceptibility shows different behaviors dep ending on the substituting transition element: the data for BaKCu3MnS4 can be fitted to the Curie-Weiss equation (mu (eff) = 2.50 mu (B) per manganese ion) while magnetic ordering occurs for BaKCu3CoS4 (T-N similar to 12 K). BaKCu3NiS4 exhibits temperature-independent paramagnetic behavior. (C) 2001 Academic Press behavior.