Ferromagnetic behaviour in semiconductors: a new magnetism in search of spintronic materials

The future of the spintronic technology requires the development of magnetic semiconductor materials. Most research groups have focused on diluted magnetic semiconductors because of the promising theoretical predictions and initial results. In this work, the current experimental situation of ZnO based diluted magnetic semiconductors is presented. Recent results on unexpected ferromagnetic-like behaviour in different nanostructures are also revised, focusing on the magnetic properties of Au and ZnO nanoparticles capped with organic molecules. These experimental observations of magnetism in nanostructures without the typical magnetic atoms are discussed. The doubts around the intrinsic origin of ferromagnetism in diluted magnetic semiconductors along with the surprising magnetic properties in absence of the typical magnetic atoms of certain nanostructures should make us consider new approaches in the quest for room temperature magnetic semiconductors. Copyright EDP Sciences/Società Italiana di Fisica/Springer-Verlag 2007