Spinel transition metal ferrite TMFe2O4 (TM= Co2+, Ni2+, Cu2+, and Zn2+) nanoparticles were prepared via a template-assisted sol-gel method followed by a calcining process, using metal nitrate precursors as raw materials. The prepared specimens were characterized using X-ray diffraction (XRD) and a vibrating sample magnetometer (VSM). Their structures, magnetic properties, crystallization kinetics, and the influence of crystal size (D) on the magnetic properties were investigated. It was found that the crystal sizes of TMFe2O4 were positively proportional to the calcined temperature and time, and the crystallization growth activation energy (E a) increased with the increase of metal ionic radius. The optimum calcination parameters were obtained to form a crystal closest to the standard crystal. Additionally, the saturation magnetization of inverse spinel structure specimens was enhanced monotonously and their coercivity showed a potential decrease trend, while there was an opposite change trend for normal spinel structure specimens.

Keywords: Transition metal ferrites, Crystallization kinetics, Magnetic properties, Nano particles.