Optical and magnetic properties of ZnO/ZnFe2O4 nanocomposite

ZnO/ZnFe2O4 nanocomposite was prepared by a simple and low cost chemical precipitation method. The prepared composite was characterized by X-ray diffraction (XRD), energy-dispersive X-ray (EDX), Raman and Fourier Transform infrared spectroscopy (FTIR). The morphology of the prepared sample was studied by scanning electron microscopy (SEM). Photoluminescence (PL) emission of the sample has been investigated at different temperatures (10-300 K) in order to determine the effect of temperature on emission properties of the prepared composite. It was found that at low temperature, the samples show stronger emissions than those at room temperature. Magnetic properties of ZnO/ZnFe2O4 nanocomposite was discussed in temperature range of 5-300 K using VSM measurement. The effective anisotropy constant Keff, extracted from the magnetization vs. magnetic field, M(B), experimental curve obtained at 5 K and using the law of saturation magnetization, was found to be 2.3 × 106 erg/cm3. The high value of anisotropy constant is attributed to the existence of uncompensated surface spin in our sample as well as the magnetocrystalline contribution (which depends on the inversion degree in ZnFe2O4). By using of a modified Langevin equation, the contribution of the surface spins was quantitatively calculated in different temperature higher than TB. It was found that as the temperature increases from 100 K to 300 K, the surface spins contribution in the total magnetization increases from 44% to 68%.