New Insight into the Electrochromic Properties of Iron Oxides

We report on the structural, optical and magnetic properties of iron oxide films that were electrochemically cycled in a LiOH aqueous solution. We found that the electrochromic phenomenon is linked to the transformation of the film morphology; it goes from round-shaped particles to platy morphology. Additionally, the following phenomena were observed: a gradual blue shift of the optical-absorption edge, an increase of the saturation magnetization and the appearance of new Raman bands. The change of these properties helped us to understand the coloration mechanism for electrochromism in iron oxides. (c) 2010 The Japan Society of Applied Physics