Materials for spintronic:: Room temperature ferromagnetism in Zn-Mn-O interfaces

In this paper we study the room temperature ferromagnetism reported on Mn-doped ZnO and ascribed to spin polarization of conduction electrons. We experimentally show that the ferromagnetic behaviour is associated to the coexistence of Mn3+ and Mn+4 in MnO2 grains where diffusion of Zn promotes the Mn4+ --> Mn3+ reduction. Potential uses of this material in spintronic devices are analysed. (C) 2006 Elsevier B.V. All rights reserved.