Abstract
The zinc-doped maghemite nanoparticles were prepared using ultrasonic radiation. As a precursor, a suspension of maghemite in an alkaline aqueous solution of zinc nitrate at pH = 9 was sonicated. They were investigated by x-ray diffraction, Mössbauer spectroscopy, high-resolution electron microscopy (HREM), and superconducting quantum interference device (SQUID) magnetometry. The results show that by using ultrasound radiation, zinc Zn2+ can substitute for Fe3+ up to a composition close to zinc ferrite (ZnFe2O4), which has a random distribution of Fe3+ ions over both A and B sublattices in the spinel structure with an inversity parameter of δ = 0.322. This leads to a maximum saturation magnetization (M s ) of 64.1 emu/g at 300 K and 73.5 emu/g at 2 K.