Electrical and magnetic properties of some first row transition metal intercalates of niobium disulphide

The resistivity, Hall effect and magnetic susceptibility have been measured as a function of temperature for the first row transition metal intercalates of niobium disulphide, M1/3NbS2 (M = Mn, Fe, Co, Ni), where the intercalate ions form an ordered superlattice. Metallic behaviour, associated with conduction in the niobium d bands, is observed, and sharp anomalies are seen at the temperatures at which the localized moments on the intercalate ions order. The Mn inter calation complex orders ferromagnetically, the Fe, Co and Ni complexes anti-ferromagnetically. The splittings of the intercalate d levels by the crystal field are proposed and possible magnetic interactions are discussed.