Hydrothermal synthesis of superparamagnetic zinc–nickel ferrite nanoparticles

Abstract

Abstract Zn 0.8 Ni 0.2 Fe 2 O 4 nanoparticles were prepared in a three-step synthesis involving the co-precipitation of metal nano-hydroxide, coating the metal nano-hydroxide with oleic acid, and hydrothermal treatment (ferritization). The nanoparticles were analyzed using X-ray diffraction, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy and transmission electron microscopy. All samples heated at temperatures from 140 °C to 180 °C were crystalline Zn 0.8 Ni 0.2 Fe 2 O 4 with particle sizes ranging from 5–8 nm. Vibrating sample magnetometry results indicated that the coercive force and remanence of the samples were close to zero, and the saturation magnetization values were high (14.20–27.12 emu · g −1 ).