Microstructure and magnetic properties of iron modified mesoporous silica obtained by one step direct synthesis

Iron-containing MCM-41 molecular sieves have been successfully synthesized by directly incorporating the metal in the initial synthesis gel. The resulting microstructures were characterized by XRD, UV–vis DR, ICP and N2 adsorption. Room temperature magnetic properties were evaluated by measuring the magnetization vs. applied magnetic field loops, up to 5 T. The results show that the structural, chemical and magnetic properties of the resulting materials strongly depend on the hydrothermal treatment time and the iron content. The hysteresis loops exhibit para-, superpara- and ferromagnetic contributions in agreement with the iron species distributions. It is found that longer hydrothermal treatments result in a stabilization of the iron into the network and in a refiner effect of the oxide particles.