The S=1 underscreened anderson lattice model for uranium compounds

Abstract

Magnetic properties of uranium and neptunium compounds showing coexistence of the Kondo e®ect and ferromagnetic order are investigated within the degenerate Anderson Lattice Hamiltonian, describing a 5f2 electronic configuration with S = 1 spins. Through the Schrie®er-Wol® transformation, both an exchange Kondo interaction for the S = 1 f-spins and an e®ective f-band term are obtained, allowing to describe the coexistence of Kondo e®ect and ferromagnetic ordering and a weak delocalization of the 5f-electrons. We calculate the Kondo and Curie temperatures and we can account for the pressure dependence of the Curie temperature of UTe.