Study of the magnetic properties of Mg, Gd, and Co doped maghemite (?-Fe2O3) nanoparticles prepared by sol-gel

The gamma-Fe2O3 magnetic nanoparticles, prepared by sol gel route, were doped with Magnesium (Mg), Gadolinium (Gd), and Cobalt (Co) oxides to enhance their magnetic properties. The X-ray diffraction, of the prepared sam-ples, show that all samples crystallized under cubic structure with P4332 space group. The morphological properties of our nanopowders were studied with TEM investigations. The average nanoparticle sizes were distributed between 15 and 23 nm for both the pure and the doped samples. The magnetization as a function of temperature and magnetic field were measured to study the effect of the doping elements on the magnetic properties. The results show that the highest magnetization (MH) of our nanoparticles increases especially with increasing Mg, Gd and Co concentration It is also observed that cobalt doping increases the magnetic coercivity by increasing the value of the coercivity field (Hc) and remanence magnetisation (Mr), which can be used in magnetic recording devices.