Effect of transition Metal (Co, Ni and Cu) doping on lattice volume, band gap, morphology and saturation magnetization of ZnO nanostructures

Herein, the effect of different TM (Co, Ni and Cu) doping on structural, optical and magnetic properties of ZnO nanostructures has been studied. Zn1−xTMxO (TM=Co, Ni and Cu) nanostructures were prepared by a microwave assisted chemical route and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy, transmission electron microscopy (TEM), Raman spectroscopy, UV-Vis and magnetization measurements. XRD and TEM analyses showed that the TM-doped ZnO nanostructures had single phase nature with the wurtzite structure. Changes in the lattice volume, bandgap energy, morphology and the saturation magnetization of Zn1−xTMxO nanostructures were found to be dependent on the type of TM dopants. Lattice volume, bondlength and bandgap determined from XRD and UV-Vis, respectively, were found to decrease as the atomic number of the dopant increased from Co to Cu. Magnetic studies showed that all the TM-doped ZnO exhibited room temperature ferromagnetism and the decreasing trend of saturation magnetization was observed with the increase of 3d electrons number from Co to Cu.