Room temperature ferromagnetism in nanocrystalline Ni-doped ZnO synthesized by co-precipitation

Ni-doped ZnO powder was synthesized by thermal co-decomposition of a mixture of bis( acetylacetonato) zinc(II) hydrate and bis(dimethylglyoximato) nickel( II) complexes. The samples were characterised by X-ray diffraction (XRD), Energy dispersion X-ray. uorescence (EDXRF), and FT-IR spectroscopy. The atomic ratio Ni/Zn of the samples was determined by the EDXRF method to be 1%, 4.3%, 7.4% and 22.5 wt%. The XRD studies show the formation of nanocrystalline (14-18 nm) of Ni-doped ZnO along with nanoparticles of NiO. By magnetic measurements, it was observed that powder contains 1%Ni, 4.3%Ni, 7.4%Ni exhibits superparamagnetic behaviour while the sample of 22.5%Ni prepared in closed atmospheric environment shows clear ferromagnetic (FM) loop at room temperature due to the formation of solid solution Zn1-xNixO. (c) 2009 Elsevier B.V. All rights reserved.