Effect of Ni Doping on Structural, Optical, and Magnetic Properties of Fe-Doped ZnO Nanoparticles

In the present work, pure ZnO, Zn 0.99Fe 0.01O (ZFO), Zn 0.99Ni 0.01O (ZNO) and Zn 0.98Fe 0.01Ni 0.01O (ZFNO) dilute magnetic semiconductors were successfully synthesized by using the wet coprecipitation method. Pure and doped samples were characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, UV-Vis spectroscopy and vibrating sample magnetometer. The X-ray diffraction (XRD) analysis of pure and doped samples confirms the formation of a hexagonal wurtzite structure, without formation of any other secondary and impurity phases. Surface morphology of pure and doped ZnO nanoparticle samples performed by scanning electron microscopy (SEM) reveals the formation of spherical nanocrystallites with clear and welldefined boundaries. Energy-dispersive X-ray spectroscopy (EDS) indicates the successful substitution of dopant Fe 2+ and Ni 2+ in the lattice site of Zn 2+ and results in the formation of single-phase Zn 1−x−yFe xNi yO. The UV-visible absorption spectra of all doped samples showed blueshift in absorption edge as compared to undoped ZnO nanoparticles. The magnetic characterization reveals and confirms the roomtemperature ferromagnetism in all doped and codoped samples. Magnetization saturation is enhanced in Ni–Fe codoped sample as compare with individual Fe and Nidoped ZnO samples which further reveals that exchange interaction between Fe and Ni ions dominates over the Fe–Fe and Ni–Ni ion interaction.