The magnetism of ultrathin Ni films grown with O surfactant

Structural and magnetic properties of Ni films on Cu(I 0 0) and Cu(I 10) with and without 0 surfactant assisted growth are studied by element specific X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD) at the 0 K edge and the Ni L-2,L-3 edges. No bulk-like NiO is formed at the surface, and 0 stays on top of the Ni films. We observe a charge transfer from Ni to 0 states at the surface. In contrast to Ni on (root2- x 2root2)R45degrees O/Cu(I 00) the total magnetization of Ni on (2 x 1) O/Cu(I 10) is enhanced for thinner Ni films. Especially, the orbital moment contributes to this enhancement. We attribute the effect to the surface roughness of the samples. Finally, we determine an induced magnetic orbital moment of the oxygen parallel to the spin and orbital moment of nickel. (C) 2004 Elsevier B.V. All rights reserved.