QUASI-PARTICLE AND THERMODYNAMIC MASS IN THE HEAVY-FERMION SYSTEM CEB6

The de Haas-van Alphen effect has been investigated in the heavy-fermion compound CeB6 in magnetic fields extending to 53 T. Absolute amplitude measurements reveal that the major sheets of the Fermi surface are not spin polarized, and that its observed volume is 1.15 +/- 0.1 electrons per formula unit. Analysis of the field dependence of the quasiparticle effective mass based on the periodic Anderson model yields, for the ratio of the characteristic temperature to the g factor, T*/g = 4.0 +/- 0.8 K, while over the field interval 31-43 T, for which the mass changes by a factor of two, the mean free path of the quasiparticles remains constant at 56 +/- 1 nm. We compare the density of states derived from the measured quasiparticle masses with that deduced from specific-heat experiments for magnetic fields below approximately 30 T, and find them to be in agreement. We conclude that the low-temperature thermodynamics of CeB6 may be understood simply in terms of the low-energy excitations of a heavy charged Fermi liquid. We note that these experiments do not support the idea of Kagan et al that a significant contribution to the low-temperature thermodynamics of Ce-based heavy-fermion systems arises from the presence in them of a neutral Fermi liquid.