Room-temperature ferromagnetism in Dy films doped with Ni

Temperature, magnetic field and spectral dependences of magneto-optical effects (MOEs) in bi-layer films Dy(1−x)Nix-Ni and Dy(1−x)(NiFe)x-NiFe were investigated, x changes from 0 to 0.06. Peculiar behavior of the MOEs was revealed at temperatures essentially exceeding the Curie temperature of bulk Dy which is explained by the magnetic ordering of the Dy layer containing Ni under the action of two factors: Ni impurities distributed homogeneously over the whole Dy layer and atomic contact of this layer with continues Ni layer. The mechanism of the magnetic ordering is suggested to be associated with the change of the density of states of the alloy Dy(1−x)Nix owing to hybridization with narrow peaks near the Fermi level character for Ni.