Trends in magnetism of free Rh clusters via relativistic ab-initio calculations

TL;DR

This study uses relativistic ab-initio calculations to analyze the magnetic properties of free Rhodium clusters, revealing that traditional correlation with coordination number does not hold, but the Stoner model remains effective.

Contribution

It demonstrates the applicability of the Stoner model to 4d Rh clusters and explores the behavior of orbital moments and intra-atomic dipole terms in these systems.

Findings

No systematic relation between local magnetic moments and coordination numbers.

The Stoner model effectively predicts magnetism in Rh clusters.

Large orbital magnetic moments antiparallel to spin moments found at some sites.

Abstract

A fully relativistic ab-initio study on free Rh clusters of 13-135 atoms is performed to identify general trends concerning their magnetism and to check whether concepts which proved to be useful in interpreting magnetism of 3d metals are applicable to magnetism of 4d systems. We found that there is no systematic relation between local magnetic moments and coordination numbers. On the other hand, the Stoner model appears well-suited both as a criterion for the onset of magnetism and as a guide for the dependence of local magnetic moments on the site-resolved density of states at the Fermi level. Large orbital magnetic moments antiparallel to spin magnetic moments were found for some sites. The intra-atomic magnetic dipole Tz term can be quite large at certain sites but as a whole it is unlikely to affect the interpretation of x-ray magnetic circular dichroism experiments based on the sum rules.