Magnetic and electronic properties of heavy fermion compound CeCu 4In and valence fluctuating compound CeNi 4In

Abstract

The CeCu 4In and CeNi 4In compounds were investigated by means of magnetization, specific heat and electrical resistivity measurements. These compounds are paramagnetic down to 2 K. CeCu 4In follows the Curie–Weiss law with μ eff = 2.40 μ B/f.u. and θ P = −27 K. The experimental value of μ eff is close to the calculated one for a free Ce 3+ ion, thus indicating the presence of well-localized magnetic moments carried by the stable Ce 3+ ions. The determined electronic heat capacity coefficient γ = 235 mJ mol −1 K −2 confirms heavy fermion character of this compound. The temperature dependence of electrical resistivity is characteristic of heavy fermion systems. Similar analysis for CeNi 4In provided μ eff = 0.89 μ B/f.u. and θ P = 0.5 K. This effective paramagnetic moment is lower than the free Ce 3+ value. The temperature dependence of resistivity is typical of the Kondo impurity system, i.e. it shows a minimum at low temperatures. The reduced effective paramagnetic moment and a small electronic specific heat coefficient γ = 16 mJ mol −1 K −2 indicate on a valence fluctuation in this compound.