Structure et magnétisme de systèmes mixtes 3d/4d et 3d/5d : une étude ab initio des alliages macroscopiques aux nanoparticules

Abstract : Various mixed Co/Rh and Co/Pt systems from the macroscopic surface and bulk alloys down to the small nanoclusters have been studied within the density functional theory. Co atoms generally induces significantly enhanced magnetic moments at their 4d/5d neighbors, while they retain their magnetic moment even in an highly mixed environment, leading to substantial average moments in good agreement with earlier experiments. The respective influences of alloying and reduced coordination effects are discussed. Emphasis is given to the determination of the strong interplay between structure, chemical order and magnetic properties. The oscillating RKKY-like character of the Co-induced moments, combined to their significant enhancement at the surface, leads to a particularly complex magnetic pattern. The Co doping effect appears to be the most efficient for large, low-magnetic 4d/5d particles, even if in this case small antiparallel induced moments may slightly moderate the magnetic enhancement.
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Samuel Dennler. Structure et magnétisme de systèmes mixtes 3d/4d et 3d/5d : une étude ab initio des alliages macroscopiques aux nanoparticules. Physique [physics]. Université Paul Sabatier - Toulouse III, 2004. Français. ⟨tel-00266714⟩

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