Synthesis, electrical, and magnetic properties of new quaternary alkali metal mixed-transition metal sulfides [ACoCuS2 (A = K, Rb, Cs) and KCo2-xCuxS2 (0.5 ≤ x ≤ 1.5)] are reported. The synthesis was accomplished by sulfurization of a mixture of corresponding alkali metal carbonate and copper and cobalt oxides. All of the phases form in the tetragonal ThCr2Si2-type structure in space group I4/mmm. The electrical resistivity measurements show that the new phases are semiconducting, with room temperature resistivities ρRT ∼ 10-2 Ω · cm; KCo0.5Cu1.5S2 is metallic with a metal-to-nonmetal transition at ∼120 K. Seebeck measurements indicate that the majority of charge carriers are holes. The temperature dependence of magnetic susceptibility shows an anomalous transition to the ferromagnetic state in the ACoCuS2 phases. The electrical and magnetic properties of the new quaternary phases are compared with those of ternary ACo2S2 (A = K, Rb, Cs).
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Condensed Matter Physics
- Physical and Theoretical Chemistry
- Inorganic Chemistry
- Materials Chemistry