Preparation and characterisations of magnetic nanofluid of zinc ferrite for hyperthermia

Zinc ferrite (ZnFe2O4) nanoparticles were synthesised by using solution gelation and the self-combustion technique. The resulting zinc ferrite nanoparticles were structurally analysed by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and vibrating sample magnetometry for structural, morphological and magnetic properties, respectively. The XRD pattern shows that the prepared sample has a spinel monophasic cubic structure, and the broadening of X-ray peaks indicates the nanocrystalline size of the particles to be on the order of 13nm. FE-SEM analysis shows spherical-type grains and confirms the nanocrystalline nature with an average grain size of 24nm. The energy-dispersive X-ray analysis spectrum indicates the purity of the sample and the presence of the desired ions in good proportions. The magnetisation-field strength (M-H) hysteresis loop shows enhanced magnetisation with the superparamagnetic nature of zinc ferrite nanoparticles compared with previous literature reports. The saturation magnetisation value (M s) was estimated to be 23·25emu/g. The obtained nanoparticles of zinc ferrite were used to prepare nanofluids with water as a base fluid (2mg/ml concentration). Magnetic hyperthermia studies were carried out using an induction heating system. The induction heating results show that a small amount (2mg/ml) of zinc ferrite nanoparticles can achieve a 42°C temperature for 258s at 4·0kA/m.