Characterization of magnetism and electronic properties of a ternary transition metal chalcogenide Rb₂Ni₃S₄

The process of preparing specimens of Rb₂Ni₃S ₄ single crystals grown by the flux method was reconsidered to clarify the magnetic and electronic properties of this nickel sulfide. Specimens obtained by removing fluxes with water were confirmed to have a residual ferromagnetic moment, as previously reported by the present authors. Specimens peeled a surface of as-grown crystals off by taking advantage of the quadratic layer characteristic of this crystal were ascertained to be diamagnetic and to exhibit magnetic properties intrinsic to Rb ₂Ni₃S₄. However, the temperature dependence of the specific resistivity of the latter sample is similar to that of the former. Through examination of the experimental results, Rb₂Ni ₃S₄ was identified as a nonmagnetic semiconductor in a low spin 3d⁸ configuration of Ni²⁺.