A combined micro-Raman, X-ray absorption and magnetic study to follow the glycerol-assisted growth of epsilon-iron oxide sol-gel coatings
Jesús López‐Sánchez, Aída Serrano, Adolfo del Campo, Álvaro Muñoz‐Noval, Eduardo Salas‐Colera, Mariona Cabero, M. Varela, M. Abuín, G.R. Castro, Juan Rubio‐Zuazo, O. Rodrı́guez de la Fuente, N. Carmona
Abstract
Epsilon iron oxide (ε-Fe2O3) coatings on Si(100) substrates are obtained by an easy one-pot sol-gel recipe assisted by glycerol in an acid medium. Glycerol, given its small dimensions, enables the formation of ε-Fe2O3 nanoparticles with a size of a few nanometers and the highest purity is reached in coatings after a densification treatment at 960 °C. The structural and compositional evolution up to 1200 °C is studied by confocal Raman microscopy and X-ray absorption spectroscopy techniques, correlating the existing magnetic properties. We report a novel characterization method, which allows monitoring the evolution of the precursor micelles as well as the intermediate and final phases formed. Furthermore, the inherent industrial technology transfer of the sol-gel process is also demonstrated with the ε-Fe2O3 polymorph, impelling its application in the coatings form.