Regensburg 2007 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 20: Correlated Electrons - Poster Session

TT 20.4: Poster

Mittwoch, 28. März 2007, 14:00–17:45, Poster A

Coexistence of ferromagnetism and underscreened Kondo effect in uranium compounds — •Natalia Perkins¹, Jose Roberto Iglesias², and Bernard Coqblin³ — ¹Technische University of Braunschweig, Braunschweig,38106, Germany — ²Instituto di Fisica, Universidade Federal do Rio Grand do Sul, 91501-970, Porto Alegre, Brazil — ³Laboratoire de Physique des Solides, Universite Paris-Sud, Batiment 510, 91405 Orsay, France

Coexistence between ferromagnetic order and Kondo behavior has been experimentally observed in some uranium compounds, like UTe or UCu0.9Sb2. 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.