Theory of Metamagnetism in the Heavy Fermion Compound CeRu_2Si_2

抄録

Metamagnetism of heavy fermions is investigated using the Anderson lattice model in which the anisotropy of the hybridization matrix element, together with electron-lattice coupling, is taken into account. Within the leading-order approximation in the 1/N-expansion, it is found that the incoherent part of the f electron becomes relevant above a critical field H_M, while it is irrelevant below H_M.Consequently, both magnetization and magnetostriction show abrupt increases with increasing H at H_M.The results are in good agreement with the experimental data of CeRu_2Si_2.