The variation in color of Fe3O4 nanopowder from black to reddish brown
1. Intrinsic Color: Black Bulk (micron-scale) pure Fe3O4(Magnetite) appears deep black under visible light. Reason: Fe3O4 is a narrow-bandgap semiconductor (bandgap ≈0.1≈0.1 eV), which absorbs light across the entire …