Formation of FeAs and Fe crystallites in GaAs–Fe composite structures and their roles in light-enhanced magnetization

The model for the light-enhanced magnetization observed in the GaAs–Fe composite structures (S. Haneda et al., J. Appl. Phys. 87 (2000) 6445.) has been constructed on the basis of studies on the nucleation process of Fe and GaAs, as well as the detail magnetization behavior. We have found that the Fe clusters with the average diameter of View the MathML source is responsible for the light-enhanced magnetization. The role of antiferromagnetic FeAs is to magnetically suppress the interaction between the clusters at low temperatures.