Tin Oxide Based Transparent Ferromagnetic Semiconductor Thin Films by Spray Pyrolysis

ABSTRACTCobalt- and manganese-incorporated SnO2 thin films exhibiting room temperature ferromagnetism have been prepared by spray pyrolysis technique. Analysis of structural, magnetic and electrical properties of Sn1−xCoxO2−δ thin films indicates that the origin of ferromagnetism, seen for x<0.125, lies in the polarization of free carriers, leading to the necessary exchange interaction. The films exhibit a Curie temperature > 500K. The XRD study indicates that Sn1−xCoxO2−δ films with x<0.125 is single phasic with no evidence of any Co clusters or magnetic oxides, which supports the intrinsic nature of the ferromagnetism. The electrical transport studies indicate that extra electrons are generated on Co-incorporation in the SnO2 lattice. In the case of Sn1−xMnxO2·δ films, ferromagnetism is observed in a narrow range of manganese (0.075≤x≤0.10) with an associated increase in carrier concentration. The detailed analysis of various properties suggests that Mn-ions have been incorporated in the SnO2 lattice, and there is absence of any Mn-clusters, Mn-related secondary phases.