抄録
The metamagnetic behavior of CeRu2Si2 andthe non Fermi-liquid behavior of CeNi2Ge2are described by the periodic Coqblin-Schrieffer modelwith anisotropic c-f exchange interactionin the mean-field theory.Only the Kramers doublet of MJ=± 5/2for the 4f states of Ce ions is considered, for the case of which the density of quasi-particle stateshas singularity of | ω |-1/2 around the effective f-level energy.In the asymmetric case applicable to CeRu2Si2, the chemical potential reaches the singularityat a finite magnetic field, at whichthe magnetization shows a metamagnetic-like increase.On the other hand, in the symmetric case applicable to CeNi2Ge2, the chemical potential is on the singularity at zero magnetic field, and non-Fermi-liquid-like behaviorsemerge in the susceptibility and the specific heat.
