Pressure-Induced Electronic Transition in CeAl2

Abstract

The room-temperature resistance of CeAl2 passes through a faint maximum around 60 kBar and falls off at higher pressure. Strong anomalies were previously reported for the temperature-dependence of the resistivity under pressure up to 15 kBar by Nicolas-Francillon et al. It has been found that these anomalies gradually disappear with even higher pressures. They are entirely suppressed at pressures exceeding ≃120 kBar resulting in a R-T characteristic being very similar to that of the nonmagnetic compound LaAl2. There is a striking similarity to the R vs. T behavior of pure cerium in the β or γ phase on the one hand and in the a phase on the other hand. We conclude that CeAl2 undergoes a continuous electronic transition with pressure just as Ce above the critical point.