Structural and Magnetic Properties of 57Fe-Doped TiO2 and 57Fe/Sn-Codoped TiO2 Prepared by a Soft-Chemical Process

Graphical Room-temperature ferromagnetism (RTFM) was found in 57 Fe-TiO 2 and 57 Fe/Sn-TiO 2 materials prepared by a soft-chemical solution method. Their magnetic properties were found to decrease with increasing degree of 57 Fe doping. Fe 3+ –oxygen vacancy (V O )–Fe 3+ centers are responsible for the observed RTFM. A series of 57 Fe-doped TiO 2 and 57 Fe/Sn-codoped TiO 2 materials were prepared by a soft-chemical solution process with various 57 Fe concentrations from 0.1 to 1.0 at.-% and a fixed Sn concentration of 2.0 at.-%. In this process, an aqueous H 2 O 2 solution reacts with iron and titanium or iron, tin, and titanium precursor compounds to produce peroxopolymetallic acids. The structures and magnetic properties of the products were characterized by magnetic-moment measurements, X-ray diffraction, and Raman and Mössbauer spectroscopy. The results showed that all samples consisted of a rutile phase (and a trace amount of anatase in 57 Fe-TiO 2 ). All samples exhibited hysteresis loops in the M – H curves, which demonstrated the presence of room-temperature ferromagnetism. In addition, their magnetic properties decreased with increasing degree of 57 Fe doping. Oxygen vacancies were considered to be responsible for the presence of ferromagnetism.