Surface segregation and magnetism of an alloy surface: PtNi(001)

In this work we studied the atomic segregation and magnetization of the PtN i(001) surface, using the full-potential linearized augmented plane wave (F LAPW) method with GGA. Results of total energies for different film thickne sses (1, 3, 5, and 7-layers) and surface compositions (with 100%, 50% and 0 % of Pt concentration) indicate that the Pt-100% terminated surface is the most stable configuration for PtNi(001), a result which is consistent with the experimental data. The calculated magnetic moments of surface (with Pt atoms) and subsurface (with Ni atoms) layers are 0.41 and 0.85 mu (B), resp ectively. The d-band hybridization between Ni and Pt atoms was found to pla y an important role in determining the magnetism. (C) 2001 Elsevier Science B.V. All rights reserved.