MODIFICATIONS OF THE ELECTRONIC-STRUCTURE OF NI CU(001) AS A FUNCTIONOF THE FILM THICKNESS/

We report angle-dependent near-edge x-ray-absorption fine-structure me asurements of tetragonal Ni films [0.6-14.4 monolayers (ML)] grown on a Cu(001) surface. The analysis of the Ni L-3.2 white-line intensities show that the density of 3d holes (n(h)) increases almost by 20% from a submonolayer to a 5 ML thick film, clearly showing that a constant value of n(h) cannot be used in sum rules to estimate spin and orbital momentum contributions to the local magnetic moment by magnetic circu lar dichroism, Therefore, caution must be exercised before claiming an enhancement of spin and orbital magnetic moment at lower film coverag es. Also, a difference in the number of d holes having in-and out-of-p lane symmetries and modifications in the near-edge features was observ ed.