Ab initio studies of the electronic structure and magnetic properties of bulk and nano-particle CeCo₂

We have carried out a theoretical study of the electronic structure and magnetic properties of both bulk and supercell slab CeCo₂. The calculations are based on first-principles density functional theory with generalized gradient approximation (GGA) and also with the GGA + U scheme. Both GGA and GGA + U calculations predict bulk CeCo₂ to be nonmagnetic, in agreement with experiments. However, calculations for a supercell slab with a 14 Å thickness, show that the system becomes ferrimagnetic. In particular, the local magnetic moments on all the Ce and Co atoms in the thin film are pronounced. This suggests that surface effect may play a significant role in the magnetism observed in nano-particle CeCo₂.