Theoretical Study of Magnetic Ordering of Cu₂Sb-type Intermetallic Compounds

Electronic band structures of the Cu₂Sb-type intermetallic compounds are calculated by using a self-consistent augmented plane wave (APW) or a linearized APW (LAPW) method. In order to clarify the driving forces for different kinds of magnetic orderings in the Cu₂Sb-type compounds, the instability of the non-magnetic phase against formationof the magnetic orderings are studied on the basis of the Hubbard Hamiltonian. The magnetic phase diagram is constructed as a function of the intra-atomic Coulomb interaction and the electron number. The bonding nature of the electronic band near the Fermi level as well as a nesting effect of the Fermi surface plays the important role in causing thedifferent kinds of magnetic orderings observed in the Cu₂Sb-type compounds.