Mapping the valence state distribution down to the atomic resolution in a ferrimagnetic hematite-ilmenite thin film : (a) HAADF image showing the position of the metallic atomic columns; (b) elemental map in false colors showing the position of the O atoms in red, of the Fe atoms in blue and of the Ti atoms in green; (c) EELS spectrum of the Fe L23 line in black on one metallic column displaying the presence of both Fe²⁺ and Fe³⁺ as it is made of the addition of both their signature with the corresponding weighted siderite (Fe²⁺) and hematite (Fe³⁺) signature; (d to f) Fe²⁺, Fe³⁺ and Fe²⁺/Fe³⁺ maps illustrating the charge order (from [73], courtesy Laura Bocher).