The relationship between magnetic behaviour and local structure around Fe ions in Fe-doped TiO2 rutile

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

PHYSICA B - CONDENSED MATTER

ELSEVIER SCIENCE BV

Año: 2009 vol. 404 p. 2838 - 2840

0921-4526

The magnetic and structural characterization of Ti1xFexO2 (x ¼ 0.025, 0.05, 0.07, 0.125, and 0.15)samples prepared by mechano-synthesis using TiO2 and Fe2O3 as starting materials are reported. XANES measurements performed at the Fe K-edge show that Fe ions are in 3+ oxidation state in the 7 at% Fe-doped sample and in a mixture of 2+ and 3+ oxidation states in the other samples. EXAFS results show the incorporation of Fe ions substituting Ti ones in the rutile TiO2 structure. They also reveal a strong correlation between the number of oxygen nearest neighbours and the Fe2+ fraction, i.e the number of oxygen near neighbours decreases when the Fe2+ fraction increases. All samples present ferromagnetic-like behaviour at room temperature. We found a clear dependence between saturation magnetization and coercivity with the fraction of Fe2+ and/or the number of Fe near neighbour oxygen vacancies.