X-ray photoemission and magnetometric studies of valence changes in Ce(Cu 1− x Ni x ) 4Ga

• Published in: Journal of magnetism and magnetic materials Vol. 323; no. 12; pp. 1678 - 1681
• Main Authors: Toliński, T., CheŁkowska, G., Falkowski, M., Kowalczyk, A.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.06.2011; Elsevier
• Subjects: Clean metal, semiconductor, and insulator surfaces; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electron and ion emission by liquids and solids; impact phenomena; Electron states; Exact sciences and technology; Heavy fermion; Magnetic properties and materials; Magnetic susceptibility; Magnetically ordered materials: other intrinsic properties; Photoemission and photoelectron spectra; Physics; Rare earth compound; Strongly correlated systems; heavy fermions; Valence fluctuation; Valence fluctuation, kondo lattice, and heavy-fermion phenomena; X-ray photoemission; X-ray photoemission; Rare earth compound; Heavy fermion; Valence fluctuation; Magnetic susceptibility; Nickel alloys; Cerium alloys; Hybridization; Gallium alloys; Hexagonal lattices; Copper alloys; Rare earth alloys; Chemical composition; Mixed valence; Transition element alloys; X-ray photoelectron spectra
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2011.01.036

The compounds Ce(Cu 1− x Ni x ) 4Ga crystallize in the hexagonal CaCu 5-type structure for the whole doping range 0≤ x≤1. The border compounds CeCu 4Ga and CeNi 4Ga represent a heavy fermion and fluctuating valence systems, respectively. We report on the studies of the valence evolution in Ce(Cu 1− x Ni x ) 4Ga 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. ► Ni substitution for Cu in CeCu 4Ga leads to the loss of Ce 4f states localization. ► Valence fluctuations visible in the XPS of Ce 3d states. ► Magnetic susceptibility measured and the valence resolved up to 1000 K. ► Importance of the temperature independent susceptibility