Structural, optical, and magnetic properties of Mn-doped NiO thin films prepared by sol-gel spin coating

Manganese (Mn)-doped Nickel (II) Oxide (NiO) thin films are prepared using sol-gel spin coating method. The structural, morphological, optical, and magnetic properties of these films are studied using XRD, FE-SEM, Micro-Raman spectroscopy, UV–visible spectroscopy, Photoluminescence (PL) spectroscopy, and VSM analysis. XRD results reveals that doping of Mn retains the cubic phase of NiO but changes its lattice parameters and introduces strain in the NiO films. The crystallite size of NiO films decreases from 19.86 nm to 12.11nm as the doping concentration of Mn changes from 0 to 15 mol%. XPS and Micro-Raman spectrum confirm the successful incorporation of Mn ions into NiO. The intensity of the PL spectra decreases with increasing Mn content. The violet, blue, and green emissions in the luminescence spectrum indicate the presence of vacancy defects corresponding to nickel and oxygen. Our research shows that these defects influence the magnetic properties of the doped thin films of NiO. The results from the vibrating sample magnetometer (VSM) explain the ferromagnetic behavior of the Mn doped NiO thin films. [Display omitted] •The crystallite size decreases and band gap energy increases with Mn doping.•Single species heterovalent Mn doping has been suggested as the origin of room-temperature ferromagnetism.•Oxygen vacancy or nickel vacancy defects and BMPs are the sources of inducing ferromagnetism in Mn doped NiO thin films.