Optimized synthesis of the elusive ε-Fe2O3 phase via sol-gel chemistry

is an element of-Fe2O3 nanoparticles embedded in a SiO2 matrix have been synthesized by sol-gel chemistry and high temperature heat treatments. Virtually pure is an element of-Fe2O3 (in excess of 93%) is obtained, although a two-phase mixture, is an element of-Fe2O3 + alpha-Fe2O3, is observed for Fe2O3/SiO2 ratios greater than 37 wt %. The is an element of-Fe2O3 nanoparticles are stable up to similar to1600 K. Optimized is an element of-Fe2O3 nanoparticles are ferrimagnetic, with a Curie temperature T-c approximate to 510 K, and remarkably high values of room-temperature coercivity, H-c = 20 kOe.