Structural, vibrational, and magnetic study in Mg-doped NiO nanoparticles

Abstract

Undoped and Mg-doped nickel oxide nanopowders of Ni_1-xMg_xO(x = 0.00, 0.01, 0.02, 0.03, 0.05, and 0.10) were synthesis by the sol-gel method. The prepared samples shows a face-centered cubic structure and the average crystallite size was achieved 10–13 nm using the Williamson-Hall method. At room temperature, 0.56 emu.g⁻¹ of magnetization was observed for Mg-doped x = 0.10 at 1.5 KOe applied field. The band gap value of 4.21 eV was found for x = 0.03 samples from UV visible spectra and decreases with Mg concentration. The O K edge and Ni L_2,3 spectra illustrate the unique changes as a function of Mg-doped NiO from the XAS measurement. The defects were related to nickel vacancies Ni³⁺ and the presence of a hole state in O K edge by doping observed from the XAS analysis. The band 1P (TO + LO)) from the Raman spectra confirmed the increases in crystallinity and the presence of surface state or disorder states with doping leads to show room temperature ferromagnetism and the sample is useful for magneto-optic devices applications.