Influence of (Mg, Cu) codoping on the structural, optical and magnetic properties of NiO nanoparticles synthesized by coprecipitation method

Pure and (Mg, Cu) codoped NiO nanoparticles were prepared via the co-precipitation method. The prepared nanoparticles were investigated by XRD, TEM, SEM-EDX, XPS, FTIR, Raman, UV-vis, PL and VSM. NiO cubic structure forms with no impurities or secondary phases. (Mg, Cu) codoping of NiO lowers its crystallite size and causes variation in the Ni stoichiometry as well as formation of O vacancies. The optical transmittance is enhanced up to 87% for x = 0.08, becoming beneficial for transparent electrodes. The bandgap and Urbach energies increase from 3.51 to 3.66 eV and 0.43-0.54 eV, respectively, whereas the optical dielectric constant decreases from 7.72 to 7.25 with enhancement of the electron-phonon interaction. Weak ferromagnetic contribution exists, and the ferromagnetic origin is explained by the BMP model. Coercivity and saturation magnetization decrease from 438.42 to 30.12 Oe and 0.267 to 0.178 emu/g, respectively, which is beneficial for data storage applications.