Ferromagnetism in Eu intercalated NbS₂

The layered compound NbS2 can be intercalated with Eu, Yb and Sr from liquid ammonia solution at low temperatures. The intercalated species are predominantly divalent ions and produce an expansion in c axis of ∼ 3A. Eux (NH3)y NbS2 (x ≥ y) compounds with x ≳ 0.4 order ferromagnetically below 8°K. Diamagnetic intercalated species lower the superconducting transition temperature of pure NbS2 whereas paramagnetic species completely destroy the effect. High temperature reactions of Eu with NbS2 always produce ferromagnetic EuS as an impurity phase and obscure the inherent low temperature properties of Eu intercalated NbS2. © 1973.