INSTITUTO DE FISICA LA PLATA
Unidad Ejecutora - UE
congresos y reuniones científicas
XAFS study of Co, Ni, Cu or Zn doped TiO2 films
C. E. RODRÍGUEZ TORRES, A. F. CABRERA, L. A. ERRICO, F. GOLMAR, S. DUHALDE, M. RENTARÍA Y F. H. SÁNCHEZ.
Congreso; XVII Reunión Anual de Usuarios del LNLS, LNLS; 2007
A variety of semiconducting materials, called diluted magnetic semiconductors(DMS) combine two properties: semiconductivity and magnetism. Many researchgroups have focused their e®orts on doping TiO2 with transition metals. Much ofthe work has been concentrated on Co-doped TiO2 ¯lms, in which ferromagnetismat room temperature has been con¯rmed ¯rst for anatase and later also for ru-tile phase ¯lms. On the other hand some authors have reported remarkable roomtemperature ferromagnetism on pure TiO2, HfO2 and In2O3 oxides ¯lms and alsoin ¯lms doped with non-magnetic impurities. All the theoretical and experimentalresults point out the important role of oxygen vacancies on the origin (or presence)of magnetism, then it is crucial to know the local environment of the impurities inthe ¯lms.In this work we present an XAFS characterization of the local environment ofthe M atoms (M=Co, Ni, Cu or Zn) in doped anatase TiO2 thin ¯lms. All these¯lms present ferromagnetism at room temperature. We did not found evidencesof metallic clusters in any case. The oxidation state is +2 and the local oxygencoordination is similar to MO (CoO, NiO, CuO or ZnO) but, with the exceptionof Cu, the similitude with these oxides is only in the short range.1