Specific Heat of Ce0.8La0.2Al3 in Magnetic Fields: A Test of the Anisotropic Kondo Picture

The specific heat C of Ce_0.8La_0.2Al₃ has been measured as a function of temperature T in magnetic fields up to 14 T. A large peak in C at 2.3 K has recently been ascribed to an anisotropic Kondo effect in this compound. A 14-T field depresses the temperature of the peak by only 0.2 K, but strongly reduces its height. The corresponding peak in C/T shifts from 2.1 K at zero field to 1.7 K at 14 T. The extrapolated specific heat coefficient γ = T-->0C/T increases with field over the range studied. We show that these trends are inconsistent with the anisotropic Kondo model.