Synthesis of zinc ferrite particles with high saturation magnetization for magnetic induction hyperthermia

ZnFe 2 O 4 particles have drawn much attention due to their low toxicity and soft ferrite nature, but the low saturation magnetization limits their bio-applications. Herein, the heat treatment was employed to improve the saturation magnetization of ZnFe 2 O 4 particles synthesized by hydrothermal method. After heat treatment, the saturation magnetization of ZnFe 2 O 4 increases from 11.1 emu/g to 126.0 emu/g after heat treatment at 1200 °C, which is the maximum one reported up to now. The XRD and XPS analyses suggest that the increment in saturation magnetization may result from the migration of Zn 2+ from A -site to B -site incurred by the heat treatment. According to the results of the magnetic heating studies, the saturation magnetization enhancement increased ZnFe 2 O 4 heating efficiency. The in vitro cell experiments demonstrate the obtained ZnFe 2 O 4 magnetic particles exhibit negligible cytotoxicity to HaCaT cells.