On the microscopic model of Fe and Ni: the possible breakdown of the ferromagnetic fermi-liquid picture

A new model of strong itinerant ferromagnetism, taking into account the presence of a narrow density-of-states peak at E F , which is due to merging of van Hove singularities, is proposed. The states of the peak (e g -type states for Fe) are treated within the framework of the Hubbard model with strong correlations. The role of the non-quasi-particle states, which lie near E F and are not described by the theory of the ferromagnetic Fermi liquid, is investigated. In particular, experimental data on the spin polarization of conduction electrons and T-dependence of resistivity are discussed.