LAUSR

In this present work, we have focused on the effect of cobalt substitution in the nickel aluminate system. The aluminate samples were synthesized by the chemical precipitation method. The structural and optical properties of the NiAl2O4, CoAl2O4, and Ni0.5Co0.5Al2O4 samples were studied through X-ray diffraction and UV-DRS absorbance spectral analysis. The XRD pattern confirms the cubic phase with the space group of Fd-3 m through its analysis of the diffraction peaks. The UV absorption peaks around at 360, 480, 551, 580, and 621 nm extend the formation of NiAl2O4, CoAl2O4, and Ni0.5Co0.5Al2O4 system. The surface morphological images of the samples were scanned by using the scanning electron microscope. The room temperature magnetic nature of the aluminate samples was carried out using VSM, and the observed result reveals a weak ferromagnetic and super-paramagnetic nature for NiAl2O4 and Ni0.5Co0.5Al2O4, respectively. The temperature dependence impedance spectra and AC conductivity were measured using an impedance analyzer at selected temperatures, and that reveals the bulk resistance of the grain and the grain boundary region of the sample. The observed results were analyzed and discussed.