Synthesis, characterization and magnetic properties of KFeO₂ nanoparticles prepared by a simple egg-white solution route

In this work, nanoparticles of potassium ferrite (KFeO₂) were synthesized by a simple egg-white solution method upon calcination in air at different temperatures of 500, 600, and 700ºC for 2 h. The effects of calcination temperature on structural and magnetic properties of the synthesized KFeO₂ nanoparticles were investigated. By varying the calcination temperature, X-ray diffraction (XRD) and transmission electron microscopy (TEM) results indicated the changes of crystallinity and morphology including particle size, respectively. Significantly, the reduction of particle size of the synthesized KFeO₂ was found to have a great influence on the magnetic properties. At room temperature, the synthesized KFeO₂ nanoparticles prepared at 600ºC exhibited the highest saturation magnetization (M_S) of 26.24 emu•g^-1. In addition, the coercivity (H_C) increased from 3.51 to 16.89 kA•m^-1 with increasing calcination temperature up to 700ºC. The zero-field-cooled (ZFC) results showed that the blocking temperatures (T_B) of about 125 and 85 K were observed in the samples calcined at 500 and 600ºC, respectively. Therefore, this work shows that the egg-white solution method is a simple, cost effective, and environmental-friendly for the preparation of KFeO₂ nanoparticles.