Evolution from a localized to an intermediate valence regime in Ce2Cu2−xNixIn

Abstract

Polycrystalline samples of the solid solution Ce2Cu2−xNixIn were studied by means of x-ray powder diffraction, magnetic susceptibility and electrical resistivity measurements performed in a wide temperature range. Partial substitution of copper atoms by nickel atoms results in a quasi-linear decrease of the lattice parameters and the unit cell volume of the system. The lattice compression leads to an increase in the exchange integral and yields a reversal in the order of the magnetic 4f1 and nonmagnetic 4f0 states, being in line with the Doniach phase diagram. In the localized regime, where an interplay of the Kondo scattering and the crystalline electric field effect occurs, the rise in the hybridization strength is accompanied by a relative reduction in the scattering conduction electrons on excited crystal field levels.