Re-entrant and spin-glass-like behaviour of the Anderson lattice

Abstract

The magnetic properties of intermediate valence systems described by the periodic Anderson model are studied within a mean-field approximation for a wide range of localized 4f-level occupation nf. It is found that the linear susceptibility chi 0 shows divergence at two critical temperatures Tc1 and Tc2, indicating instability in magnetic ordering. Ferromagnetic order exists for Tc1<or=T<or=Tc2, indicating a re-entrant behaviour. For another range of nf, the system exhibits spin-glass-like magnetic response with almost divergent non-linear susceptibility as the external magnetic field goes to zero, at a temperature T0 where the linear susceptibility has a cusp-like behaviour. As nf is scanned, it is found that Tc1 and Tc2 merge for a particular value of 4f-level position. This temperature Tg (=Tc1=Tc2) is found to increase with the increase in hybridization between the localized and band states. It is observed that the linear response for T>or=T0 can be represented by a scaling relation.