Magnetic and electronic properties of heavy fermion compound CeCu4In and valence fluctuating compound CeNi4In

The CeCu4In and CeNi4In compounds were investigated by means of magnetization, specific heat and electrical resistivity measurements. These compounds are paramagnetic down to 2 K. CeCu4In follows the Curie-Weiss law with mu(eff) = 2.40 mu B/f.u. and theta(P) = -27 K The experimental value of mu(eff) is close to the calculated one for a free Ce3+ ion, thus indicating the presence of well-localized magnetic moments carried by the stable Ce3+ ions. The determined electronic heat capacity coefficient gamma = 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 CeNi4In provided mu(eff) = 0.89 mu(B)/f.u. and theta(P) = 0.5 K. This effective paramagnetic moment is lower than the free Ce3+ 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 gamma = 16 mJ mol(-1) K-2 indicate on a valence fluctuation in this compound. (C) 2009 Elsevier B.V. All rights reserved.