Influence of single-site and cooperative magnetic effects on phonons in CeNi-based compounds
Abstract
A study of the temperature evolution of acoustic phonons and Ce valence value in the intermediate-valence compound Ce0.85La0.15Ni have been performed. The substitution of Ce by La does not suppress the intermediate valence state but decreases the valence value. A significant softening for most of the acoustic modes has been found in Ce0.85La0.15Ni with respect to reference compound LaNi at room temperature. The analysis of obtained data using analogous ones for CeNi allow to distinguish between effects of influence on CeNi phonon frequencies caused by intermediate-valence single-ion phenomenon and magnetic correlation between Ce unstable-valence ions. It appears that intermediate valence effect results in reduction of phonon frequencies in general, while inter-ion magnetic interaction leads to an extra contribution to the value of frequencies for selected phonon modes. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
