CO ULTRA-THIN FILMS ON PD(111) - MAGNETIC-ANISOTROPY OF THE CO PD INTERFACE/

The magnetic anisotropy of Co ultra-thin films on Pd(111) is studied i n the framework of a d-electron tight-binding Hamiltonian which includ es hopping, exchange, and spin-orbit interactions on the same electron ic lever. We perform self-consistent calculations from which the magne tic anisotropy energy (MAE) is obtained in a non-perturvative fashion as difference between electronic energies. The magneto-anisotropic beh avior is determined for several ultra-thin film systems: Pd-n/Co-m/Pd, when n and m refer to the number of Pd and Co layers, respectively. I n agreement with experiment we found for n = 0 a strong perpendicular anisotropy for m = 1, 2, 3 whereas for m = 4 an in-plane direction of the magnetization is obtained. Pd-1/Co-4/Pd only shows perpendicular a nisotropy when relaxation effects are taken into account. The spin and orbital magnetic moments of Co-m and those induced at the Pd atoms at the interface are analized as a function of film thickness.