Perpendicular magnetic anisotropy in nanoclusters caused by surface segregation and shape

TL;DR

This study uses kinetic Monte Carlo simulations to explore how surface segregation and shape influence perpendicular magnetic anisotropy in CoPt3 nanoclusters, providing insights for optimizing growth conditions.

Contribution

It demonstrates how surface segregation and cluster shape interplay to induce PMA, guiding experimental growth parameter optimization.

Findings

PMA occurs within a specific growth temperature window.

Pt surface segregation significantly affects magnetic anisotropy.

Cluster shape, especially aspect ratio, influences PMA.

Abstract

The growth of binary alloy clusters on a weakly interacting substrate through codeposition of two atomic species is studied by kinetic Monte Carlo simulation. Our model describes salient features of CoPt$_3$-nanoclusters, as obtained recently by the molecular-beam epitaxy technique. The clusters display perpendicular magnetic anisotropy (PMA) in a temperature window of growth favorable for applications. This temperature window is found to arise from the interplay of Pt surface segregation and aspect ratio for cluster shapes. Conclusions are drawn how to optimize growth parameters with respect to PMA.