X-ray photoemission and magnetometric studies of valence changes in Ce(Cu1-xNix)4Ga

The compounds Ce(Cu1-xNix)(4)Ga crystallize in the hexagonal CaCu5-type structure for the whole doping range 0 <= x <= 1. The border compounds CeCu4Ga and CeNi4Ga represent a heavy fermion and fluctuating valence systems, respectively. We report on the studies of the valence evolution in Ce(Cu1-xNix)(4)Ga employing the X-ray photoemission spectroscopy (XPS) and magnetic susceptibility measurements. The photoemission of the Ce 3d peaks shows a gradual decrease of the occupation of the f states with Ni content. Simultaneously, the hybridization strength and the low temperature magnetic susceptibility are reduced. Within the valence band spectrum a transition from the dominance of the Cu 3d to the dominance of the Ni 3d states is well visible with the traces of the Ce 4f(1) states for up to x=0.5. (C) 2011 Published by Elsevier B.V.