Effect of nickel on the magnetic state of dysprosium in Dy1−x Nix-Ni bilayer films

Abstract

This paper reports on the results of investigations into the temperature and spectral dependences of the magnetic circular dichroism in Dy1−xNix-Ni bilayer films prepared through thermal sputter deposition of components under ultrahigh vacuum. The distribution of the components over the layer thickness is examined by Auger spectroscopy. The nickel content x in Dy1−xNix layers varies from 0.005 to 0.06. It is shown that, in the temperature range 80–300 K, the contribution made to the magnetic circular dichroism by a Dy1−xNix layer in a bilayer film with a nickel content higher than the threshold value is approximately equal to the magnetic circular dichroism observed in an isolated Dy1−xNix film at temperatures below the temperature of the phase transition to a ferromagnetic state (∼100 K). This phenomenon is explained by magnetic ordering in the Dy1−xNix layer of the bilayer film due to the combined effect of two factors, namely, the incorporation of nickel into a dysprosium layer and the presence of a continuous nickel sublayer in the film.