Possible observation of the quadrupolar Kondo effect in dilute quadrupolar system Pr(x)La(1-x)Pb3 for x <or= 0.05.

We have studied non-Fermi-liquid (NFL) behavior in Pr(x)La(1-x)Pb3 with Gamma3 quadrupolar moments in the crystalline-electric-field ground state. The specific heat C/T shows NFL behavior in the very dilute region for x <or= 0.05, which is scaled by a characteristic temperature T* in each Pr concentration. The application of a magnetic field leads to a sharp increase of C/T , demonstrating the shift of the entropy existing in the lower temperature region at H=0 T . Moreover, Fermi-liquid behavior emerges at higher fields, in contrast with NFL behavior at lower fields. The observed features indicate that NFL behavior is caused by the quadrupolar Kondo effect.