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

Abstract Precision magnetoresistance (MR) Δ ρ / ρ ( H , T ) and Hall coefficient R H measurements have been carried out for archetypal Ce-based heavy fermion compounds—CeCu 6− x Au x ( x = 0 , 0.1 and 0.2) and CeAl 3 on high quality polycrystalline samples over a wide temperature range 1.8–300 K in magnetic fields up to 70 kOe. It was found the Brillouin–type component of MR Δ ρ / ρ ( H , T ) ∼ H 2 that can be consistently interpreted in the frameworks of a simple relation between resistivity and magnetization - Δ ρ / ρ ∼ M 2 obtained by K. Yosida (Phys. Rev. 107 (1957) 396). A local magnetic susceptibility χ loc ( T , H ) = ( 1 / H ( d ( Δ ρ / ρ ) / d H ) ) 1 / 2 deduced from the data obtained is compared with the data of bulk susceptibility measurements χ ( T , H ) . The study of anomalous Hall effect allows us to establish for the first time a complicated activation type behavior of R H and estimate the bound energies E a 1 , 2 of many body states at E F for CeAl 3 and CeCu 6 heavy fermion compounds. Microscopic parameters of charge carriers transport (effective masses, relaxation time) and localization radius a p 1 , 2 * of these heavy quasiparticles ( a p 1 * ( T > 5 0 K ) ∼ 1.5 A and a p 2 * ( T 5 0 K ) ∼ 1 5 A both for CeCu 6 and CeAl 3 ) were also estimated.