Evolution from localized to intermediate valence regime in Ce2Cu2-xNixIn

TL;DR

This study investigates how substituting nickel for copper in Ce2Cu2-xNixIn alters its electronic and magnetic properties, transitioning from localized to intermediate valence regimes through structural and spectroscopic changes.

Contribution

It provides new insights into the valence transition mechanism in Ce-based intermetallics induced by chemical substitution and lattice compression.

Findings

Lattice parameters decrease linearly with Ni substitution.

Magnetic exchange interactions increase, reversing 4f state order.

Hybridization strength rises, affecting Kondo and crystal field effects.

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 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 takes place, the rise in the hybridization strength is accompanied with relative reduction in the scattering conduction electrons on excited crystal field levels. (c) 2011 IOP Publishing Ltd.