Co monolayers and adatoms on Pd(100), Pd(111) and Pd(110): Anisotropy of magnetic properties

TL;DR

This study uses relativistic ab initio calculations to explore how different Pd surface orientations affect the magnetic properties of Co monolayers and adatoms, revealing significant anisotropy in magnetic behavior.

Contribution

It provides a detailed analysis of how crystallographic surface orientation influences magnetic moments and anisotropy in Co/Pd nanostructures, highlighting the role of the T_alpha term.

Findings

Surface orientation affects orbital magnetic moments significantly.

Magnetocrystalline anisotropy energy varies dramatically with surface orientation.

The T_alpha term can cause strong apparent anisotropy in XMCD measurements.

Abstract

We investigate to what extent the magnetic properties of deposited nanostructures can be influenced by selecting as a support different surfaces of the same substrate material. Fully relativistic ab initio calculations were performed for Co monolayers and adatoms on Pd(100), Pd(111), and Pd(110) surfaces. Changing the crystallographic orientation of the surface has a moderate effect on the spin magnetic moment and on the number of holes in the d band, a larger effect on the orbital magnetic moment but sometimes a dramatic effect on the magnetocrystalline anisotropy energy (MAE) and on the magnetic dipole term T_alpha. The dependence of T_alpha on the magnetization direction alpha can lead to a strong apparent anisotropy of the spin magnetic moment as deduced from the X-ray magnetic circular dichroism (XMCD) sum rules. For systems in which the spin-orbit coupling is not very strong, the T_alpha term can be understood as arising from the differences between components of the spin magnetic moment associated with different magnetic quantum numbers m.