Laser synthesis of magnetic iron oxide nanopowders

Magnetic iron oxide nanopowders are synthesized by the laser ablation of a target made of a coarse Fe$_2$O$_3$ powder. The geometric characteristics of the nanopowders and their yield are studied over a wide air pressure range ((1–34) $\times$ 10$^4$ Pa) in an evaporation chamber. The phase compositions of the nanopowders and the conditions under which their chemical composition is closest to magnetite Fe$_3$O$_4$ are determined. The specific saturation magnetization and the coercive force of some iron oxide nanoparticles are measured.