Preparation and Physical Characterizations of Superparamagnetic Maghemite Nanoparticles

Superparamagnetic maghemite nanoparticles were prepared by chemical co-precipitation, followed by a temperate oxidation stage, and investigated using FE-SEM, XRD, TGA, VSM, and M $\ddot{o}$ ssbauer spectroscopy. Through SEM image and XRD analysis, its average particle size was found to be 13.9 nm. While VSM magnetic measurement showed typical superparamagnetic behavior at room temperature, M $\ddot{o}$ ssbauer spectroscopic investigation revealed that non-vanishing magnetic hyperfine structure were retained. Cation distribution estimated from M $\ddot{o}$ ssbauer spectroscopy confirmed the formation of maghemite nanophase in the sample.