Low-temperature properties of the dilute quadrupolar system PrxLa1−xPb3

Abstract We have studied the low-temperature properties of PrxLa1−xPb3 with the ground state of a non-Kramers Γ3 doublet for the Pr concentration for 0⩽x⩽1. From the concentration dependence of the specific heat, the quadrupolar ordering, which is observed at T Q =0.4 K in PrPb3, is concluded to persist only for x∼0.98. For a wide range of Pr concentration for 0.1⩽x⩽0.95, the specific heat shows a T-linear variation below 0.5 K with a large coefficient, which is almost reproduced by the model for amorphous materials with a random configuration of two-level system. For x⩽0.05, C/T shows a non-Fermi liquid behavior with the monotonous enhancement of C/T with decreasing temperature, which is probably caused by Kondo effect arising from the correlation between the Γ3 moments and the conduction electrons.