Role of the electronic state of cerium in the magnetic properties of CeNixPt1-x compounds

We present in this work an x-ray absorption spectroscopy investigation performed at the L1,3 edges of Ce in the intermetallic compounds CeNixPt1-x. This study provides a direct microscopic probe of the cerium electronic state that is found to be trivalent up to x≤0.9 and an intermediate valence for higher Ni content. The modification of the Ce L3- and L1-edge absorption profiles has been correlated with the density of conduction electrons and with the modification of the hybridization between the orbitals of Ce and the conduction band. Our results stressed that the behavior of the CeNixPt1-x series is in agreement with the Doniach diagram only up to x≤0.9. Moreover, the transition to nonmagnetism is due to the progressive screening of the 4f shell as the result of the competition between exchange interactions and the Kondo effect and not to the change of cerium valence