Microstructure and magnetic properties of fe nanoparticles synthesized by chemical vapor condensation

Nano-sized Fe particles were synthesized by Chemical Vapor Condensation (CVC) using the precursor of iron pentacarbonyl (Fe(CO)(5)) as the source under a flowing helium atmosphere. The effect of CVC processing parameters on the formation of nanoparticles was studied. Microstructures and magnetic states were investigated systematically by means of XRD, HRTEM, DTA-TGA, Mossbauer spectroscopy and VSM. We synthesized the nanoparticles with nearly spherical shape, core-shell type structure and 5-13 nn in mean size by using liquid nitrogen cooling. Average particle size increased with increasing the decomposition temperature of the precursor. The magnetic states of Fe nanoparticles changed from ferromagnetism to superparamagnetism with the particle size and microstructure. The effect of particle size on the saturation magnetization and coercivity of nanoparticles were also discussed.