Influence of carbon intercalation on the structural and magnetic properties of Ni3Al

The structural and magnetic properties of the series compounds with nominal composition AlCxNi3 (x=0, 0.025, 0.05, 0.075, 0.1, 0.2) have been investigated. All samples share the same space group Pm3 m, while the lattice parameter a is found to increase monotonously with x. Both the Curie temperature TC and the spontaneous magnetic moment per Ni atom at 5 K, μNi, decrease with increasing x. As x>0.05, the long-range ferromagnetic order disappears and the samples become exchange-enhanced Pauli paramagnets. It may be attributed to the reduction of the density of states (DOS) at the Fermi level, N(EF), due to the increasing Ni 3d–C 2p hybridization.