Susceptibility measurements in Pr_xLa_1-xInAg ₂ with Γ₃ doublet ground state

We have measured the susceptibility and magnetization of Pr _xLa_1-xInAg₂ at Pr concentrations x=1 and 0.1 down to T ∼ 0.5 K by SQUID magnetometer with a home-made ³He insert. The susceptibility above T = 15 K is well reproduced by the crystal-electric-field level scheme with a non-Kramers Γ₃ doublet in the ground state for each concentration, while that below T = 15 K shows a non-Fermi-liquid (NFL) behavior with - ln T-dependence at low magnetic field. With increasing magnetic field, - ln T-dependence is suppressed and - T^1-2-dependence appears at H = 7 T The magnetization at T = 0.5 K increases with increasing magnetic fields up to H = 7 T, indicating that the increase of the susceptibility does not come from impurity ions. These results suggest that the quadrupolar Kondo effect is responsible for NFL behavior of the susceptibility.