The Effect of Co Doping on the Structural, Optical, and Magnetic Properties of Fe-Doped ZnO Nanoparticles

In the present work, pure ZnO, Zn0.99Fe0.01O (ZFO), and Zn1-x-y Fe (x) Co (y) O (x = 0.01, y = 0.01, 0.03, 0.05) Fe-Co co-doped ZnO dilute magnetic semiconductors were successfully synthesized by using the wet co-precipitation method. Pure and doped samples were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectrometry, UV-Vis spectroscopy and vibrating sample magnetometer. The X-ray diffraction (XRD) analysis of pure and doped samples confirms the formation of hexagonal wurtzite structure, without formation of any other secondary and impurity phases. The surface morphology of pure and doped ZnO nanoparticles samples was performed by scanning electron microscopy (SEM) and reveals the formation of spherical nanoparticles with clear and well-defined boundaries. Energy dispersive X-ray spectrometry (EDX) indicates the substitution of dopant Fe2+ and Co2+ successfully in the lattice site of Zn2+ and results in the formation of single-phase Zn1-x-y Fe (x) Co (y) O. The UV-Visible absorption spectra of all doped and co-doped samples showed blueshift in absorption edge as compared to undoped (pure) ZnO nanoparticles. The magnetic characterization reveals and confirms the room-temperature ferromagnetism (RTFM) in all doped and co-doped samples. Magnetization saturation increases with increase in Co concentration in Fe-doped sample as compared with individual Fe-doped ZnO sample which further reveals that exchange interaction between Fe and Co ions dominates over the Fe-Fe ion interaction.