Thermal properties of metamagnetic transition in heavy-fermion systems

Abstract

In order to investigate the metamagnetic anomaly (MA) observed in several heavy-fermion compounds, field dependence of specific heat C(B) and magnetocaloric effect have been measured in the prototypical 4f-electron compound CeRu 2Si 2, and compared to that of a 5f-electron metamagnet UCoAl. In the C/T versus B curves, an unexpected double-peak structure is found in CeRu 2Si 2, suggesting that MA is closely related to a sharp peak in the density of states of the hybridized quasiparticle bands. On the other hand, for UCoAl, only a small decrease in C/T is observed, although both compounds exhibit similar bulk magnetic properties.