Effect of anisotropy in the S=1 underscreened Kondo lattice

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:372

Article

Thomas, Christopher^1,2  da Rosa Simoes, Acirete S.³  Lacroix, Claudine^4,5  Iglesias, Jose Roberto³  Coqblin, Bernard⁶ 

[1] CEA Saclay, Inst Phys Theor, F-91191 Gif Sur Yvette, France

[2] Univ Fed Rio Grande do Norte, Int Inst Phys, BR-59078400 Natal, RN, Brazil

[3] Univ Fed Rio Grande do Sul, Inst Fis, BR-91501970 Porto Alegre, RS, Brazil

[4] Univ Grenoble Alpes, Inst Neel, F-38042 Grenoble, France

[5] CNRS, Inst Neel, F-38042 Grenoble, France

[6] Univ Paris 11, CNRS, Phys Solides Lab, F-91405 Orsay, France

关键词: Underscreened Kondo effect;    Anisotropy;    Uranium;    Neptunium;    Strong correlated system;   

DOI  :  10.1016/j.jmmm.2014.07.028

来源: Elsevier

【 摘 要 】

We study the effect of crystal field anisotropy in the underscreened S=1 Rondo lattice model. Starting from the two orbital Anderson lattice model and including a local anisotropy term, we show, through Schrieffer-Wolff transformation, that local anisotropy is equivalent to an anisotropic Rondo interaction (J(parallel to) not equal J(perpendicular to)) The competition and coexistence between ferromagnetism and Rondo effect in this effective model is studied within a generalized mean-field approximation. Several regimes are obtained, depending on the parameters, exhibiting or not coexistence of magnetic order and Rondo effect. Particularly, we show that a re-entrant Rondo phase at low temperature can be obtained. We are also able to describe phases where the Rondo temperature is smaller than the Curie temperature (T-K < T-c). We propose that some aspects of uranium and neptunium compounds that present coexistence of Rondo effect and ferromagnetism can be understood within this model. (C) 2014 Elsevier B.V. All rights reserved.

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