Green sol-gel synthesis using Moringa oleifera gum and modified structural, magnetic and optical properties of Co-Zn aluminates

The Co _1-xZn _xAl ₂O ₄ spinel (x = 0, 0.25, 0.5, 0.75 and 1) was synthesized using Moringa oleifera gum by the sol-gel chemical route. The characterization of the investigated samples was performed by TG-DTA, XRD, XPS, FTIR, FESEM, and VSM techniques. The XRD pattern reveals cubic spinel structure with space group Fd 3 ̅ m and a good crystallinity. Lattice parameter values linearly increase with increase in Zn concentration. The EDAX spectrum confirms purity of the prepared samples with nonexistence of the elements other than Co, Zn, Al and O. The FTIR spectrum confirms the cubic spinel structure of the aluminates. Magnetic studies showed that the saturation magnetization, as well as the coercivity of the investigated samples, is decreasing with the increasing Zn substitution. The band gap energies obtained from the UV vis absorption spectra are increasing due to phase purity and systematic variation of the lattice parameter. Moreover, the values of band gap energies suggest the possible use of the aluminates as the optical and photoluminescence materials.