Anisotropic Magnetic Field Dependence Of Specific Heat In The Cubic Symmetric Quadrupolar Kondo Compound Pr0.05la0.95pb3

We studied the dependence of the electronic specific heat C-el/T on the magnetic field up to H = 8T in a dilute quadrupolar compound Pr0.05La0.95Pb3 with a non-Kramer Gamma(3) doublet in the crystal-electric-field ground state. The magnetic field dependence of C-el/T with -In T-divergent non-Fermi liquid (NFL) behavior is strongly anisotropic in all three directions of the magnetic field. In H parallel to[100] and [111], the suppression of -In T dependence appears at T similar to 0.65 K in H = 4T and 0.48 K in H = 6T, respectively, whereas in H parallel to [110] it survives at temperatures as low as the lowest temperature, T similar to 0.2 K. The observed features can be understood by considering the characteristics of the cubic symmetric quadrupolar Kondo effect, which are closely associated with the suppression of the NFL behavior owing to the splitting of the Gamma(3) doublet, which depends on the direction of the magnetic field, via the Van Vleck process with excited multiplets.