An adequate interpretation of charge transport for a dilute La1-xCexB6 system

Precision measurements of charge transport characteristics (resistivity and Seebeck coefficient) have been carried out on the high quality single crystals of the so-called dilute Kondo system La1-xCexB6 (x≤0.1) in a wide temperature range 1.8-300 K. At low temperatures, it was shown that instead of Kondo-type logarithmic contribution to resistivity Δρ∼-ln T the magnetic component obeys the power law Δρ∼T-a, which corresponds to the regime of weak localization of charge carriers with the critical exponent values a=0.47-0.49 for x≤0.1. An asymptotic behavior of Seebeck coefficient S∼-ln T found for these dilute magnetic compounds at intermediate temperatures is compared with S(T) dependence observed for the dense system CeB6. The data obtained for La1-xCexB6 are analyzed in terms of Kondo-impurity model and alternative spin-polaron approach