Cobalt nano-clusters on metal supported Xe monolayers: influence of the substrate on cluster formation kinetics and magnetism

TL;DR

This study investigates how substrate type influences the formation, magnetism, and anisotropy of cobalt nanoclusters grown on Xe buffer layers on Ag(111) and Pt(111) surfaces, combining microscopy, magnetic measurements, and calculations.

Contribution

It provides new insights into how substrate interactions affect cobalt nanocluster growth and magnetic properties during buffer layer assisted deposition.

Findings

Cluster formation is governed by substrate interactions when Xe layer is thin.

Magnetic moments and anisotropy are affected by cluster-substrate interactions.

Perpendicular magnetization is observed for Co on Pt(111) due to interface anisotropy.

Abstract

The growth dynamics of submonolayer coverages of Cobalt during buffer layer assisted growth on Ag(111) and Pt(111) substrates is investigated by variable temperature scanning tunneling microscopy in the temperature range between 80 and 150 Kelvin. It is found that attractive cluster-substrate interactions can govern the cluster formation on the Xe buffer layer, if the Xe layer is sufficiently thin. The interpretation of the microscopy results are supported by x-ray magnetic circular dichroism which monitors the effect of cluster-substrate interactions on the formation of magnetic moments and magnetic anisotropy of Co nanocluster during the different stages of growth. {\it Ab-initio} calculations show that the cluster magnetism is controlled by the interface anisotropy, leading to perpendicular magnetization for Co on Pt(111). Limits of and new potential for nanocluster fabrication by buffer layer assisted growth are discussed.