Spin moments, orbital moments and magnetic anisotropy of finite-length Co wires deposited on Pd(110) -: art. no. 100

The ground-state spin moments [S-z], orbital moments [L-z] and magnetic anisotropy energy (MAE) of Co-N one-dimensional (1D) clusters (N less than or equal to 12) deposited on the Pd(110) surface are determined in the framework of a self-consistent, real-space tight-binding method. Remarkably large total magnetic moments per Co atom, M-z = (2[S-z] + [L-z])/N = 2.8-2.9 mu(B), are obtained, which can be understood as the result of three physically distinct effects. The first and leading contribution is given by the local spin moments [S-iz] at the Co atoms i = 1, N (2[S-iz]Co similar or equal to 1 6 mu(B)). Second, significant spin moments are induced at the Pd atoms i > N close to the Co-Pd interface, which amount to about 25% of M-z (2[S-iz](Pd) = 0.2-0.3 mu(B)). Finally, enhanced orbital magnetic moments [L-iz] are responsible for approximately 20% of M-z. In the case of the Co atoms, [L-iz](Co) = 0.28-0.33 mu(B) is almost a factor of three larger than the Co bulk orbital moment, while in Pd atoms [L-iz](Pd) = 0.05 mu(B) represents about 15% of the total local moment mu(iz) = 2[S-iz] + [L-iz]. These results and the associated MAEs are analysed from a local perspective. The role of the cluster-surface interactions is discussed by comparison with the corresponding results for free-standing wires. Particularly in the case of monatomic 1D Co chains we observe that the lowest-energy magnetization direction (easy axis) changes from in line to off plane upon deposition on Pd(110). Wire-substrate hybridizations are therefore crucial for the magneto-anisotropic behaviour of 1D magnetic nanostructures on metallic substrates.