Magnetic studies of polymer-coated Fe nanoparticles synthesized by microwave plasma polymerization

Static and dynamic magnetic experiments were conducted on polymer-coated Fe nanoparticles synthesized by a microwave plasma method. Transmission electron microscopy indicates the formation of 15-20 nm particles and agglomerated clusters. The field-dependent magnetization (M-H) data show the presence of sharp switching at low fields (similar to 60 Oe) followed by a gradual approach to saturation. A saturation magnetization of M(s)similar to 80 emu/g is obtained for the nanopowder. Dynamic transverse susceptibility using a radio-frequency resonant method provides evidence for sharp switching fields and a broad distribution in anisotropy fields. These results indicate that the polymer coating plays an effective role in the underlying magnetic response of the particles. (C) 2001 American Institute of Physics.