Room-temperature ferromagnetic properties in Mn-doped rutile TiO2-δ thin films

Room-temperature ferromagnetic properties of Mn-doped reduced titanium dioxide (Ti1-xMnxO2-delta) thin films with rutile structure synthesized by a sol-gel method have been detected for a limited range of Mn composition (x). The Ti1-xMnxO2-delta films were found to be p-type semiconducting with hole concentration near 10(19) cm(-3). The observed ferromagnetism in the Ti1-xMnxO2-delta films is not related to the hole concentration but related to x. The room-temperature ferromagnetism is attributable to magnetic polaron formed by trapped electron in oxygen vacancy and magnetic ions around it. Thus, the existence of oxygen vacancies is necessary for the room-temperature ferromagnetism. (c) 2007 Elsevier B.V. All rights reserved.