THERMAL-PROPERTIES OF METAMAGNETIC TRANSITION IN HEAVY-FERMION SYSTEMS

In order to investigate the metamagnetic anomaly (MA) observed in seve ral heavy-fermion compounds, field dependence of specific heat C(B) an d magnetocaloric effect have been measured in the prototypical 4f-elec tron compound CeRu2Si2, and compared to that of a 5f-electron metamagn et UCoAl. In the C/T versus B curves, an unexpected double-peak struct ure is found in CeRu2Si2, suggesting that MA is closely related to a s harp peak in the density of states of the hybridized quasiparticle ban ds. On the other hand, for UCoAl, only a small decrease in C/T is obse rved, although both compounds exhibit similar bulk magnetic properties . (C) 1998 Elsevier Science B.V. All rights reserved.