Preparation, magnetic and optical properties of layered oxychalcogenides SmCuOCh (Ch = S or Se)

This paper reports on the synthesis and the electrical, magnetic and optical properties of SmCuOS and SmCuOSe. The magnetic properties reveal that Sm is in its 3+ oxidation state (μtheo = g√J(J + 1) = 0.85 μB; g = 2/7) with a large Van Vleck contribution, and exclude the possibility of a divalent oxidation state for samarium (Sm2+; 7F0 state, g = J = 0, μeff = 0). l properties were studied by means of diffuse reflectance and photoluminescence spectra in the UV–vis range. The electrical measurements show that the two samarium copper oxychalcogenides, SmCuOSe and SmCuOS are semiconductors with optical band gap (Eg) values of 2.60 and 2.90 eV, respectively.