Synthesis, Structure, and Room Temperature Ferromagnetism of Mn and/or Co Doped ZnO Nanocrystalline

Abstract

Nanostructures of pure and (Mn, Co) doped and codoped ZnO have been prepared by chemical coprecipitation method. The crystal structure, morphology, and ferromagnetism of the prepared samples were investigated by using X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy, and vibrating sample magnetometer. The X-ray diffraction results demonstrated that all samples having a single phase with hexagonal wurtzite structure of ZnO. FTIR spectra showed the characteristic absorption bands of ZnO in different samples. The TEM images revealed that pure and Co-doped ZnO samples having uniform nanoparticle shapes with an average particle size of 18–20 nm. whereas, Mn-doped ZnO sample has nanorod structure and (Mn, Co) codoped ZnO sample has a mixture of nanoparticle and nanorod structures. The magnetic hysteresis loop of pure ZnO nanoparticles at room temperature revealed a saturation magnetization of 0.22 emu/g and a coercivity of 91.6 Oe. Alternatively, the hysteresis loops of Zn 0.99Mn 0.01O, Zn 0.99Co 0.01O, and Zn 0.98Mn 0.01Co 0.01O samples illustrated more pronounced magnetic properties with saturation magnetization of 0.788, 0514, and 0.918 emu/g and coercivity of 141.9, 452.5, and 185.6 Oe, respectively. The effects of doping ions on the structure and ferromagnetism of the investigated samples are discussed.