Highly anisotropic magnetic states of Co dimers bound to graphene-vacancies

TL;DR

This study uses relativistic density functional calculations to explore the magnetic states of cobalt atoms and dimers on graphene vacancies, revealing stable magnetic bi-stability with high anisotropy barriers.

Contribution

It demonstrates the existence of kinetically stable cobalt dimers on graphene vacancies with significant magnetic bi-stability and anisotropy, a novel finding in this context.

Findings

Local magnetic moments form despite strong binding

Stable isomers with two cobalt atoms on the same side of graphene

Magnetic bi-stability with a 50 meV anisotropy barrier

Abstract

The adsorption behavior and the magnetic states of cobalt atoms and dimers on single vacancies in a graphene sheet are investigated by means of relativistic density functional calculations. It is found that local magnetic moments are formed in both cases, despite strong chemical binding. Of particular interest are kinetically stable isomers with two cobalt atoms attached to the same side of the graphene sheet. Magnetic bi-stability with an anisotropy barrier of about 50 meV is possible in this geometry. The feasibility of its preparation is discussed.