Phase composition, magnetic properties and thermal behavior of a novel Fe2O3–SiO2 composite material

•An Fe2O3–SiO2 nanosized composite material was prepared in an aqueous medium.•The magnetic properties of the material are controllable by synthesis conditions.•Morphology of the material causes augmentation of the iron oxides thermal stability.

An Fe2O3–SiO2 composite was prepared by controllable Fe3+ and SIO32-hydrolysis. Scanning (SEM) and transmitting (TEM) electron microscopy images showed particles with an average size of 10–30 nm composed of an iron-containing core covered with a silica shell. The FT-IR, vibrating sample magnitometer (VSM), thermogravimetric analysis and Mössbauer spectroscopy study confirmed that the core consisted of ferrihydrite. Heating at 300 °C did not result in any noticeable phase transitions, whereas 800 °C heating caused the formation of the maghemite γ-Fe2O3 phase. Such improvement of the thermal stability of maghemite is promising for development of heat-resistant magnetic materials.