FERMI-LIQUID DESCRIPTION FOR ITINERANT-ELECTRON MAGNETISM

On the basis of the Fermi-liquid model the magnetic susceptibility for paramagnetic or ferromagnetic metals carrying itinerant electrons is evaluated as a function of temperature. It is shown that for the paramagnetic regime, at low temperatures, the susceptibility definitely shows a maximum which is responsible for universal phenomena observed in 4d and 5d metals, Laves phase compounds and heavy-fermion compounds. The present model explains the concurrence of the susceptibility maximum and Curie-Weiss susceptibility in nearly ferromagnetic metals, the appearance of thermally induced ferromagnetism and the precise Curie-Weiss law for relatively weak ferromagnets. The Fermi-liquid effect produces logarithmic terms in the free energy with respect to temperature, magnetization M etc. Because of the M4 ln M term of the energy, some Laves phase compounds are shown to exhibit a metamagnetic transition. This term is also the origin of peculiar nonlinear magnetization curves observed for CeRu2Si2.