Structural, optical and magnetic characterizations of nanoparticles spinel Zn(1-x)MxAl2O4 (M = Co and Ni) synthesized by microwave combustion method

Abstract

Spinel Zn(1-x)MxAl2O4 (M = Co and Ni) nanoparticles were prepared using the microwave combustion technique. Different compositions of ratios with formula Zn(1-x)MxAl2O4 (0.5 ≤ x ≤ 1.0) were prepared by substitution of Zn+2 ions with Co+2 and Ni+2 ions. Structural properties of the resultant spinel compositions were characterized by Energy Dispersive X-ray, X-ray diffraction and infrared spectroscopy. The surface topology and determination of particle size of the nanopowder were characterized by high-resolution scanning electron microscope. Magnetization and spectra of the optical absorption at room temperature were measured. The effects of substitution Co+2 and Ni+2 cations on optical and magnetic properties of ZnAl2O4 spinel were studied. Analysis of UV–Vis absorbance showed that the optical band gaps of the samples decrease linearly with increasing Co+2 and Ni+2 ratios. Vibrating Sample Magnetometer study showed that an adding of Co+2 and Ni+2 ions to ZnAl2O4 leads to converse diamagnetic zinc aluminate to paramagnetic and superparamagnetic materials.