PREPARATION AND PROPERTIES OF LOW-DIMENSIONAL QUATERNARY SULFIDES: ACuMnS2 (A = K, Rb, Cs)

Three quaternary sulfides ACuMnS2 (A = K, Rb, Cs) with the ThCr2Si2-type structure were prepared from alkali metal carbonate A2CO3, MnS, and CuO by CS2/N2 sulfurization. The samples are degenerate semiconductors (ρ(RT) ≈10−1 Ω · cm). In the temperature range 100–300 K, the susceptibility of all the samples shows a weak maximum consistent with localized antiferromagnetic exchange in isolated two-dimensional manganese cluster nets. The divergence of the FC and ZFC molar susceptibilities (χFC > χZFC) for all the samples suggests spin-glass-type behavior with a well-defined freezing temperature, Tf of≈35 K. © 1997 Elsevier Science Ltd