Low-temperature synthesis of superparamagnetic Zn0.8Ni0.2Fe2O4 ferrite nanoparticles

Abstract

The crystalline nanoparticles of Ni0.2Zn0.8Fe2O4 ferrite were synthesized by chemical co-precipitation with precursor concentration of 0.1 M, then modified by 0.25 M solution of oleic acid in l-pentanol and finally heated at low temperatures 120, 140, 160 and 1800C for 6 h in autoclave. The effect of heating temperafure on crystallite size and magnetic properties of ferrite was studied. The analysis of XRD, EDS and TEM data of samples confirmed that all of samples heated at these temperatures are crystalline with particle size of 6, 6.5, 7 and 8 nm, respectively. With the particles size below 10 nm, the nanoparticles of ferrite demonstrated the superparamagnetic properties, and could be applied effectively in various fields: medicine, treatment, military etc. The magnetic properties of Ni0.2Zn0.8Fe2O4 ferrite measured by vibrating sample magnetometer (VSM) showed that the coercive force Hc and the remanence Mr of samples are about zero while the saturation magnetization Ms has values of 14.2, 25.4, 26.8 and 27.l emu/g, consequently.