Optical and Magnetic Properties of ZnO Nanoparticles Doped with Co, Ni and Mn and Synthesized at Low Temperature

Zinc oxide nanomaterials were synthesized with small amounts of magnetic ions to create dilute magnetic semiconductors (DMS), by using a low temperature sol–gel method. Conditions were controlled such that a range of amounts of Co, Ni and Mn were incorporated. The incorporation could be tracked by color changes in the powders to blue for Co, green for Ni and yellow for Mn. XRD measurements showed the ZnO has the wurtzite structure with crystallites 8–12 nm in diameter. Nanoparticles were observed by SEM and TEM and TEM showed that the lattice fringes of different nanoparticles align. Nanoparticle alignment was disrupted when high concentrations of metal dopants were incorporated. Magnetic measurements showed a change in behavior from diamagnetic to paramagnetic with increasing concentration of metal dopants.