Origin of magnetism in Al–Mn and Al–Pd–Mn quasicrystals, related crystals and liquids

Abstract Whereas most of crystalline Al(Si)–Mn and Al(Si)–Pd–Mn phases are non-magnetic, measurements show the existence of localized magnetic moments on a small fraction of the Mn atoms in quasicrystals and in a few crystalline approximants. We develop a new model that shows that an indirect Mn–Mn interaction via the conduction band is determinant for the existence or not of a magnetic moment, even when Mn–Mn distance is 5 A or more. These models allow us to understand experimental measurements.