Identification of ferric oxide polymorphs in nanoparticles prepared by sol-gel method and maximization of ε-Fe2O3 content


The effects of annealing temperature and Fe2O3 mass fraction in the initial mixture on the composition of ferric oxide polymorphs within the Fe2O3/SiO2 nanocomposite prepared by sol-gel method were investigated. The structural and magnetic properties were characterized in detail by combination of XRD, high-resolution TEM, magnetic measurements and Mössbauer spectroscopy. The ∼91% of the ε-phase was reached with the characteristic particle diameter of 25 nm. It was observed that with increasing Fe2Omass fraction, the optimal annealing temperature decreases, while the width of the particle size distribution increases.