Ferro- and Antiferromagnetism of Transition Metals and Alloys

The interaction between two neighboring localized magnetic moments in the transition metals and alloys is studied by using the Anderson model generalized to the case of fivefold degenerate d-orbitals. The effective exchange energy and the change of the localized moments due to the d-d covalent admixture are calculated by using the Hartree-Fock approximation and the Green function technique. The results are applied to interpret various ferro-and antiferromagnetic properties of the transition metals and their alloys. It is explained qualitatively why Cr and Mn are antiferromagnetic while Fe, Co and Ni are ferromagnetic. The estimated exchange energies for these 3d-metals compare fairly well with the observed values for the Curie temperatures. Various magnetic properties of 3d-alloys, including those shown in the Slater-Pauling diagram, are explained qualitatively. 1. Introduction Electronic structure of the d-electrons in the transition metals has been a subject of continuous debate. 1 ),