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Detailed Program
Paper Number : NA-P01
Time Frame : 12:00~13:30
Presentation Date : Friday, 28, November
Session Name : Nano-particles & Nano-structured Materials
Session Chair 1# : -
Session Chair 2# : -
Effect of intrinsic defects on the optical and magnetic properties of Co: ZnO nanoparticles based DMS
Dr. Rezq Aljawfi
Ibb University, Yemen
The optical and ferromagnetism in pure ZnO and Co doped ZnO nanoparticles (NPs) have been reported, The NPs were synthesized through citric-gel process. The single phase nature and the incorporation of Co2+ ions into the lattice structure of ZnO have been revealed via X-ray diffraction (XRD) analysis, energy dispersive X-ray spectroscopy (EDS) and Raman spectroscopy. Calculation based on the XRD data shows that the average crystallite sizes of pure ZnO and Co doped ZnO NPs were 19.5 and 14.6 nm respectively. The substitution of Co2+ ions affects on the PL spectrum by shifting the energy states, and significantly decreases the band gap energy. The energy deep levels (EDLs), which are created by native defects like oxygen vacancy (VO), zinc vacancy (VZn), zinc interstitial (Zni), have been estimated through PL and micro-Raman spectroscopic studies. The samples exhibit ferromagnetic (FM) hysteresis loop at 300 K, which has been discussed based on the spin-spilt conduction band model. In this model, the defects of VO and Zni intermediate the interactions between the magnetic moments of the localized electrons in highly state (3d7) of Co2+ ions. The week FM can be attributed to present a insolated ions of Co, which is paramagnetic.
Acknowledgements :