A comparison between volume and electronic concentration effects in Ce transformations

Abstract

The crossover from magnetic to non-magnetic ground states in Ce compounds is analysed within the competition between the on-site and inter-site interactions proposed by Doniach. The comparison of the evolution of the ordering temperature, as a function of pressure and alloying, was performed in more than twenty Ce systems. This systematic shows that volume (Delta V) and electronic concentration (Delta Z) effects, as the driving forces for such a transformation, present different characteristics. The maximum in the ordering temperature (T0), predicted by the model, is only observed under Delta V effects (induced by alloying or by pressure) and not under Delta Z variations. This study leads to the conclusion that the maximum in T0 cannot be considered intrinsic to a complete magnetic to non-magnetic transformation, but rather is a consequence of the Ce-Ce spacing decrease, before the wavefunction overlap turns on the hybridization mechanism.