High-quality nickel cobaltite (NixCo3−xO4, 0 ≤ x ≤ 1) nanopowders with various nickel contents have been prepared by a facile hydrothermal method, calcined in air at 300°C for 2 h, then coated on the surface of indium tin oxide sheets by electrophoretic deposition. The optical, microstructural, and magnetic properties were characterized by x-ray diffraction (XRD) analysis, ultraviolet–visible (UV–Vis) spectrophotometry, field emission-scanning electron microscopy (FE-SEM), and vibrating-sample magnetometry. The XRD patterns of the pure and Ni-doped Co3O4 powders revealed the formation of single-phase spinel structure, without any impurity phases for all samples. The position and intensity of various absorption bands in the UV–Vis spectra were influenced by the distribution of Co2+ and Ni2+ ions at tetrahedral sites of the spinel structure, revealing that O2− → Co2+ and O2− → Ni2+ transition sites were affected by increasing the Ni2+ content, thereby changing the optical properties of NixCo3−xO4. Vibrating-sample magnetometry analysis revealed that the magnetic nature of the prepared nanopowders changed from anti-ferromagnetic to very weak ferrimagnetic.
