Preparation and physical characterizations of superparamagnetic maghemite nanoparticles

Abstract

Superparamagnetic maghemite nanoparticles were prepared by chemical co-precipitation, followed by a temperate oxidation stage, and investigated using FE-SEM, XRD, TGA, VSM, and Mössbauer 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, Mössbauer spectroscopic investigation revealed that non-vanishing magnetic hyperfine structure were retained. Cation distribution estimated from Mössbauer spectroscopy confirmed the formation of maghemite nanophase in the sample.