Heavy fermions and quantum critical behavior in CeCu6-xAux (x=0-0.2) and CeAl3

Precision magnetoresistance (MR) Delta rho/rho(H, T) and Hall coefficient R-H measurements have been carried out for archetypal Ce-based heavy fermion compounds-CeCu6-xAux (x = 0, 0.1 and 0.2) and CeAl3 on high quality polycrystalline samples over a wide temperature range 1.8-300K in magnetic fields up to 70 kOe. It was found the Brillouin-type component of MR Delta rho/rho(H, T)similar to H-2 that can be consistently interpreted in the frameworks of a simple relation between resistivity and magnetization -Delta rho/rho similar to M-2 obtained by K. Yosida (Phys. Rev. 107 (1957) 396). A local magnetic susceptibility chi(loc)(T, H) = (1/H Delta rho/rho)/dH))(1/2) deduced from the data obtained is compared with the data of bulk susceptibility measurements chi(T, H). The study of anomalous Hall effect allows us to establish for the first time a complicated activation type behavior of RH and estimate the bound energies E-a1,E-2 of many body states at E-F for CeAl3 and CeCu6 heavy fermion compounds. Microscopic parameters of charge carriers transport (effective masses, relaxation time) and localization radius alpha*(p1,2) of these heavy quasiparticles (a*(p1)(T>50K)similar to 15 A and a*(p2)(T<50K)similar to 15 angstrom both for CeCu6 and CeAl3) were also estimated. (C) 2005 Elsevier B.V. All rights reserved.