The electronic structure of the intermetallic compounds GdCu and GdZn has been calculated using density functional theory and the LMTO method for the ferromagnetic and two different antiferromagnetic orderings of the Gd local moments. The ground state of GdZn is found to be ferromagnetic while GdCu is antiferromagnetic, in agreement with experiment. The reason for the stability of one or other phase is discussed in terms of density of states features near the Fermi level. The effective exchange parameter J0 is determined from the Green functions corresponding to the calculated magnetic ground states. It is explained why the d-contribution to the Gd magnetic moment is enhanced in ferromagnetic GdZn.
 

Journal of Physics: Condensed Matter, 4 2475-86, 1992.