Coexistence of ferromagnetism and underscreened Kondo effect in uranium compounds

Coexistence between ferromagnetic order and Kondo behavior has been experimentally observed in some uranium compounds, like UTe or UCuO.9SSb2. This is an unusual behavior as Kondo effect generally compete with magnetic order, for instance in Ce compounds. Here we propose underscreened Kondo lattice model, including localized S=1 spins which couple to conduction electron through an on-site Kondo coupling, while interacting among them ferromagnetically. Results are obtained for different temperatures and values of the band filling and they show that the Kondo temperature is larger than the Curie temperature, suggesting a scenario for the coexistence of Kondo effect and ferromagnetic order. (orig.)