Enhancement of band magnetism and features of the magnetically ordered state in the CeB6 compound with strong electron correlations

Precision measurements of transport and magnetic parameters of high-quality CeB6 single crystals are performed in the temperature range 1.8-300 K. It is shown that their resistivity in the temperature interval 5 K < T < T* approximate to 80 K obeys not a logarithmic law, which is typical of the Kondo mechanism of charge carrier scattering, but the law rho proportional to T-1/eta corresponding to the weak localization regime with a critical index 1/eta = 0.39 +/- 0.02. Instead of the Curie-Weiss dependences, the asymptotic form chi(T) proportional to T-0.8 is obtained for magnetic susceptibility of CeB6 in a temperature range of 15-300 K. Analysis of the field dependences of magnetization, magnetoresistance, and the Hall coefficient in the paramagnetic and magnetically ordered phases of CeB6 and comparison with the results of measurements of Seebeck coefficient, the inelastic neutron scattering coefficient, and EPR spectroscopy lead to the conclusion that the Kondo lattice model and skew scattering model cannot be used for describing the transport and thermodynamic parameters of this compound with strong electron correlations. On the basis of detailed analysis of experimental data, an alternative approach to interpreting the properties of CeB6 is proposed using (1) the assumption concerning itinerant paramagnetism and substantial renormalization of the density of electron states upon cooling in the vicinity of the Fermi energy, which is associated with the formation of heavy fermions (spin-polaron states) in the metallic CeB6 matrix in the vicinity of Ce sites; (2) the formation of ferromagnetic nanosize regions from spin polarons at 3.3 K < T < 7 K and a transition to a state with a spin density wave (SDW) at T-Q approximate to 3.3 K; and (3) realization of a complex magnetic phase H-T diagram of CeB6, which is associated with an increase in the SDW amplitude and competition between the SDW and antiferromagnetism of localized magnetic moments of cerium ions.