Optical emissions of products sputtered from Fe, Fe2O3 and Fe3O4 powders K. Hammoum, T. El Asri, A. Chahboune, H. Aouchiche and A. Kaddouri Eur. Phys. J. D, 61 2 (2011) 469-474 Published online: 17 December 2010 DOI: 10.1140/epjd/e2010-10153-8