SYNTHESIS AND MAGNETIC-PROPERTIES OF NANOSTRUCTURED MAGHEMITE

Nanocrystalline maghemite, gamma-Fe2O3, can be synthesized in a microw ave plasma using FeCl3 or Fe-3(CO)(12) as the precursor. Electron micr oscopy revealed partide sizes in the range of 5 to 10 nm. In general, this material is superparamagnetic. The magnetic properties are strong ly dependent on the precursor. In both cases the production process le ads to a highly disordered material with the consequence of a low magn etization. The assumption of a disordered structure is also supported by electron energy loss (EEL) and Mossbauer spectroscopy. The structur e of this material shows a nearly identical number of cations on tetra hedral and octahedral lattice sites.