Structural and magnetic characterization of Ti1-xFexO2 (2.5 < x <15 at. %) nanoparticles,

MUDARRA NAVARRO A. M., V. BILOVOL, A.F. CABRERA, C.E. RODRÍGUEZ TORRES, F. SÁNCHEZ

Buenos Aires, Argentina

Congreso; FMC2008-At the Frontiers of Condensed Matter, II Magnetism, Magnetic Materials and Their Applications; 2008

TiO2 is a semiconductor oxide that doped with transition metals can present ferromagnetism at room temperature, making it an interesting material for potential technological applications. In recent years, much attention has been given to iron-doped TiO2. The Fe substitution Ti in the TiO2 structure depends on multiple factors such as iron-loading, preparation method, calcination temperatures, etc. In this work, we report a magnetic and structural characterization of Ti1-xFexO2 (x= 2.5, 5, 7, 10, 12.5 and 15 at. %) powders, prepared by mechano-synthesis using TiO2 and Fe2O3 as starting materials.XAS (x-ray absorption spectroscopy) measurements performed at Fe K-edge showed that Fe ions are in 3+ oxidation state in 7 at. % Fe doped sample and in a mixture of 2+ and 3+ oxidation states for the others. EXAFS results show a good incorporation of Fe ions substituting Ti sites in TiO2 rutile structure. It was observed from hysteresis cycles that all samples showed ferromagnetic (FM) and paramagnetic (PM) behavior from temperatures between 10 and 300 K. Magnetic measurements reveal a correlation between Fe2+ presence and magnetic behavior.