The making of ferromagnetic Fe doped ZnO nanoclusters

In this letter, the authors present a study of the energetics and magnetic interactions in Fe doped ZnO clusters by ab initio density functional calculations. The results indicate that defects under suitable conditions can induce ferromagnetic interactions between the dopant Fe atoms whereas antiferromagnetic coupling dominates in a neutral defect-free cluster. The calculations also reveal an unusual ionic state of the dopant Fe atom residing at the surface of the cluster, a feature that is important to render the cluster ferromagnetic.