Non-Fermi liquid behavior in Pr-based dilute quadrupolar system

We have studied the low temperature properties of PrPb3 and PrInAg2 with the crystal-electric-field ground state of a non-Kramers Γ3 doublet diluted by non-magnetic La ions to examine the correlation between the Γ3 quadrupolar moments and the conduction electrons. In PrxLa1−xPb3, a non-Fermi liquid (NFL) behavior is observed at Pr concentrations of x≤0.05. The specific heat C/T increases monotonically below T=1.5  K, which can be scaled with a characteristic temperature T∗ defined at each concentration x. Application of magnetic field raises C/T rapidly, which demonstrates the presence of the residual entropy at lower temperatures. In PrxLa1−xInAg2, NFL behavior is confirmed for x=0.05 and 0.1 in the susceptibility below 15 K and in the specific heat below 7 K. It is supposed that the Kondo effect arising from the correlation between the dilute Γ3 moments and the conduction electrons gives rise to NFL behavior in both systems.