Structural, morphological, magnetic and electrical properties of Ni doped ZnO nanoparticles synthesized by co-precipitation method

Abstract

Weak ferromagnetic behaviour was obtained in a systematic way at room temperature by doping of ZnO with nickel (Zn1-xNixO, where x = 0.00, 0.05, 0.15 and 0.20 at.%). Results were correlated with conductivity and impedance studies. Diamagnetic to ferromagnetic change was observed with increased concentration of nickel. X-ray diffraction analysis confirmed wurtzite ZnO structure of prepared nanopowders while microstrain was increased with nickel concentration. Incorporation of nickel in ZnO structure was confirmed using EDAX analysis, while FTIR spectroscopy provided further information on functional groups. Transmission electron microscopy images showed that the particle sizes are in the range of 12-20 nm, and scanning electron microscopy analyses that grain size decreases with increase in nickel concentration. Photo luminescence studies confirmed the presence of VO and Zni defects in the prepared samples. It was concluded that the defect induced strain, grain boundaries and lower particle sizes are the reasons for weak ferromagnetic behaviour of the investigated samples.