Orbital magnetic moments and magnetic anisotropy energy in RhN and CoNPdM clusters

The orbital magnetic moments <L> and the magnetic anisotropy energy (MAE) of Rh-N (N less than or equal to 55) and Co19PdM (M = 24 and 60) are determined by using a self-consistent real-space tight-binding method. For Rh-N, <L> amounts typically 20-50% of the total magnetic moment M-z = 2 <S-z> + <L-z>. Strong oscillations as a function of N are observed with a rapid convergence to zero as the spin magnetization vanishes for N similar or equal to 40-50. In Co19PdM clusters, the magnetization per Co atom is remarkably larger than in pare Co-19. This is mainly due to the local spin moments <S-iz> induced at the I'd atoms, which amount to about 20% of the spin moment per Co atom [2<S-iz>(Pd) = (0.1-0.3)mu(B)]. Large orbital moments are found at the Co atoms, particularly at the Co/Pd interface. The anisotropy of <L> and the associated MAE's are analyzed from a local perspective.