Intermediate valences of Ce and electrical resistivity changes of Pd-Ce intermetallic compounds

The changes in Ce valence and electrical resistivity have been studied for several intermetallic compounds of Pd-Ce. The Ce valence estimated from L ₃-XANES spectra varies smoothly with Ce concentration, with the exception of H-Pd₅Ce. The extraordinarily low Ce valence of the H-Pd₅Ce was interpreted in terms of the local configuration of Ce atoms in its crystal structure. The Ce valence of the Pd-Ce intermetallic compounds showed little variation with temperature. The resistivities of H-Pd₅Ce and Pd₃Ce have negative temperature coefficients below room temperature, suggesting that the dense Kondo effect becomes distinct in Pd-Ce alloys with the Ce valence close to 3.2.