Magnetic susceptibilities in the itinerant model: Many-band effects

摘要: Explicit expressions for the longitudinal and transverse spin susceptibilities of an itinerant ferromagnet with many bands are derived by means diagrammatic techniques within random phase approximation. The Hamiltonian used is a generalization Hubbard one-band Hamiltonian. No approximation made wavevector or band index dependence form factors, both interband intraband contributions treated. expression component shows features, absent in one case, which may account discrepancy found Lowde Windsor between their experimental values contribution to neutron scattering cross section nickel, those calculated using (essentially) theory.