Magnetic, transport and electronic properties of CeAu1−xNixIn intermetallics

Highlights: •Demonstration of the full mutual solubility between CeAuIn and CeNiIn. •Determination of the magnetic and electrical properties of CeAu1−xNixIn alloys. •Determination of the electronic structure in CeAu1−xNixIn from the XPS spectra. •Finding the gradual Ni-content dependent cerium valence change in CeAu1−xNixIn. -- Abstract: Polycrystalline compounds CeAu1−xNixIn (x = 0.2, 0.4, 0.6 and 0.8) and their La-based counterparts were investigated by means of X-ray diffraction, magnetic, electrical resistivity and X-ray photoelectron spectroscopy (XPS) measurements. All these materials crystallize in the hexagonal ZrNiAl-type structure. The CeAu1−xNixIn alloys with x ⩽ 0.6 exhibit Curie–Weiss paramagnetism down to the lowest temperatures studied, while that with x = 0.8 shows a magnetic behavior characteristic of intermediate valence systems. In all the alloys, the electrical transport is influenced by Kondo effect, which for x ⩽ 0.4 transforms with decreasing temperature from incoherent to coherent scattering, while for larger x exhibits single-ion character in the entire temperature range investigated. The XPS data indicates sizable hybridization of the Ce-4f electrons with conduction band, with the average occupation factor of the 4f1 ground state systematically diminishing with increasing the Ni content