Low-temperature specific heat and resistivity studies in the [formula omitted] compounds

Abstract

The specific heat study of the hexagonal intermetallic compound CeNi 5 revealed a substantial Sommerfeld coefficient of the linear electronic term γ = 40 mJ / mol K 2 . When substituting Cu instead of Ni, the electronic term is no longer linear and the low-temperature enhancement of the electronic term becomes apparent. With the increasing Cu concentration the enhanced γ reaches 46, 95 and 700 mJ / mol K 2 for x = 0.3 , 0.4 and 0.5, respectively, in zero magnetic field. When further increasing the Cu concentration a broad peak develops on the c / T vs. T plot below T = 2 K which can be described by a quasi-doublet with the splitting of the energy levels Δ ≈ 4 K . The low-temperature electronic specific heat of the Ce ( Ni 1 - x Cu x ) 5 compounds and its behaviour in magnetic fields is discussed in terms of possible Ce-valence fluctuations.