|Título||Underscreened Kondo lattice model applied to heavy fermion uranium compounds
Perkins, Natalia B.
Iglesias, Jose Roberto
|Abstract||We present theoretical results for the underscreened Kondo lattice model with localized S=1 spins coupled to a conduction band through a Kondo coupling, JK, and interacting among them ferromagnetically. We use a fermionic representation for the spin operators and expand the Hamiltonian in terms of bosonic fields. For large values of JK, we obtain a ferromagnetically ordered solution and a Kondo regime with a Kondo temperature, TK, larger than the Curie temperature, TC. This finding suggests a scenario for a coexistence of Kondo effect and ferromagnetic order. In some uranium compounds, such as UTe or UCu0.9Sb2, this kind of coexistence has been experimentally observed: they order ferromagnetically with a Curie temperature of order TC 100 K and exhibit a Kondo behavior for T TC. The proposed underscreened Kondo lattice model accounts well for the coexistence between magnetic order and Kondo behavior and yields to a new “ferromagnetic Doniach diagram.”
|Contido em||Physical review. B, Condensed matter and materials physics. New York. Vol. 76, no. 12 (Sept. 2007), 125101 12p.
Compostos de urânio
|Tipo||Artigo de periódico
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