Mo4-x Fex nanoalloy: Structural transition and electronic structure of interest in spintronics

A systematic ab initio study of the structures and magnetic properties of Mo4-x Fex clusters (x=1-3) is reported. The linear structure of Mo4 remains stable upon substitutional doping by one and even two Fe atoms, above which a transition to the tetrahedral geometry of pure Fe4 takes place. The cluster Mo2 Fe2 is particularly interesting since, among the rich variety of isomers of different dimensionalities and magnetic orders, its ground state and first-excited state essentially differ in the magnetic coupling between the two Fe atoms across a tightly bound Mo dimer. The equivalent to the interlayer exchange coupling observed in sandwiches and multilayers is determined in this molecular magnet, whose electronic structure makes it a good candidate to be used either as a field sensor or as a spin valve in molecular spintronics. © 2009 The American Physical Society.

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