Abstract
The two quaternary transition metal chalcogenides Rb2Cu3 MS4 (M = Fe, Mn) are based on a common structural pattern consisting of two-dimensional (2D) arrangements of sulfur tetrahedra linked by edges, with the ThCr2Si2-type structure. They are prepared from alkali metal carbonate Rb2CO3 and transition metal oxides CuO, Fe2O3 or MnO by CS2/Ar sulfurization at 850°C T 900°C. The magnetic susceptibilities are directly measured as a function of the temperature. Rb2Cu3MnS4 presents a magnetic transition from a high spin (Mn2+) to the low spin state (μeff ≍ 1.5 μ B ), while the iron analog Rb2Cu3FeS4 orders antiferromagnetically at T N ≍ 6K under an applied field of one kGauss.