Ferromagnetism In bulk Co-doped ZnO

Copyright American Institute of Physics 2006.-- Final full-text of the paper available at: http://dx.doi.org/10.1063/1.2399884.The origin of ferromagnetism in diluted magnetic semiconductors is still an open question, yielding a great deal of research across the world. This work focuses on the Co-Zn-O system. Room-temperature ferromagnetism is observed after a partial reaction of Co3O4 and ZnO, which can be ascribed neither to carrier mediation nor segregated cobalt metallic clusters. Another mechanism is yielding room-temperature ferromagnetism. This mechanism is associated with a partial reaction of ZnO and Co3O4 grains, and always appears when the starting phases (Co3O4 and ZnO) are present in the sample, suggesting that interfaces are involved in the origin of the observed ferromagnetism.This work has been supported by the University Complutense through the project PR1/05/13325 and CICYT project MAT2004–04843–C02–01.Peer reviewe