Effect of pH Value on Synthesis and Properties of Zinc Cobalt Ferrite Nano Powders Prepared via Co-Precipitation Method

Abstract

The effect of pH value on the synthesis of zinc cobalt ferrite nano powder via co-precipitation method was investigated. Zinc cobalt ferrite (Co0.6Zn0.4Fe2O4) precipitated using a solution of nitrate raw materials under different pHs (pH=8, 10, 11, 12 and 14) and calcined at 750 °C for 2 hours. The obtained nano-powders were characterized by X-ray diffraction (XRD), Williamson-Hall relations and Extrapolate functions, field emission scanning electron microscopy (FESEM) and vibrating sample magnetometer (VSM) measurements. The amount of pH had a significant effect on the structural and magnetic properties of the synthesized powders. At pHs 8 and 10, a tensile strain and above that a compressive strain was created in the system. By changing the tensile strain to compression the crystallite diameter increased, so that the crystallite diameter increased from 19.3 nm at pH 8 to 47.8 nm for pH =11. The HC of the all samples was in the range of 140-150 Oe. The saturation magnetization, anisotropy and Bohr magneton constants were 100.38 emu/gr, 15357.70 erg/Oe and 4.27, respectively for the synthesized sample at pH=11, which were higher than the other samples. These changes are due to the effect that pH has on the parameters of the crystallite diameter, particle size and also on the cation distribution of the ions in tetrahedral/octahedral spaces.