Growth, structure and magnetism of ε-Fe2O3 in nanoparticle form

We present a novel and easy synthetic path to prepare epsilon-Fe2O3 (similar to 90%) with a small portion of alpha-Fe2O3 nanoparticles embedded in an amorphous silica matrix. An exhaustive structural study reveals the higher relative concentration of the epsilon-phase, with an average particle size of 17 nm. Confocal Raman microscopy and X-ray absorption spectroscopy are presented as novel techniques to characterize the epsilon-polymorph. The magnetic properties have been studied in a wide range of temperatures (5-1000 K), detecting blocking effects (similar to 135 K), collapse effects (50-125 K), Morin (similar to 268 K) and Neel (similar to 505 K) transitions.