Magnetic properties and crystallization kinetics of Zn0.5Ni0.5Fe2O4

Precursor of nanocrystalline Zn0.5Ni0.5Fe2O4 was obtained by grinding mixture of ZnSO4 center dot 7H(2)O, NiSO4 center dot 6H(2)O, FeSO4 center dot 7H(2)O, and Na2CO3 center dot 10H(2)O under the condition of surfactant polyethylene glycol (PEG)-400 being present at room temperature, washing the mixture with water to remove soluble inorganic salts and drying it at 373 K. The spinel Zn0.5Ni0.5Fe2O4 was obtained via calcining precursor above 773 K. The precursor and its calcined products were characterized by differential scanning calorimetry (DSC), Fourier transform infrared (FT-IR), X-ray diffraction (XRD), and vibrating sample magnetometer (VSM). The result showed that Zn0.5Ni0.5Fe2O4 obtained at 1073 K had a saturation magnetization of 74 A center dot m2 center dot kg-1. Kinetics of the crystallization process of Zn0.5Ni0.5Fe2O4 was studied using DSC technique, and kinetic parameters were determined by Kissinger equation and Moynihan et al. equation. The value of the activation energy associated with the crystallization process of Zn0.5Ni0.5Fe2O4 is 220.89 kJ center dot mol(-1). The average value of the Avrami exponent, n, is equal to 1.59 +/- 0.13, which suggests that crystallization process of Zn0.5Ni0.5Fe2O4 is the random nucleation and growth of nuclei reaction.