Studying the Effect of Cobalt Doping on Optical and Magnetic Properties of Zinc Oxide Nanoparticles

Nano-crystalline powders of Zn1-xCoxO with 0.0x0.07 have been synthesized by sol-gel method. X-ray diffraction patterns of the prepared samples confirm the formation of pure single phase hexagonal crystalline structure without any secondary phases were detected. The crystallite size was calculated from the X-ray data analysis, it was decreased by increasing the cobalt concentration. The hexagonal shape of the Co doped ZnO samples was confirmed using the micrographs of the high-resolution transmission electron microscope. Vibrational spectra of prepared samples shows a stretching mode at 426 cm(-1), which was assigned to the ZnO complex using Fourier transforms infrared spectra. The energy band gap was calculated using the diffuse reflectance measurements and it was found depending on cobalt dopant ions. Finally the magnetic properties were carried out using a vibrating sample magnetometer. The M-H loops showed ferromagnetic behavior for all Cobalt concentrations doped ZnO at room temperature and diamagnetic behavior for pure ZnO.