3d transition-metal intercalates of the niobium and tantalum dichalcogenides. I. Magnetic properties

The magnetic susceptibilities, parallel and perpendicular to the layers of the first-row transition-metal intercalates, M1/3TaS2 (M = V, Cr, Mn, Fe, Co, Ni), Mn1/4TaS2, M1/3NbS2 (M = V, Cr) and Fe1/4NbSe2, have been measured as a function of temperature. The V, Cr and Mn intercalation complexes order ferromagnetically and the Co and Ni complexes order antiferromagnetically. The Fe intercalates show both types of magnetic behaviour. The magnetic properties are associated with localized moments on the intercalate ions. A simple crystal-field model of the splitting of the d levels on the 3d ions is discussed which accounts for much of the magnetic behaviour. Possible exchange interactions are examined.