Abstract
The current work presents the optical, photoluminescence and ferromagnetic properties of Zn1-xNixO samples with (0.00 <= x <= 0.20). The samples are well crystallizing in hexagonal wurtzite structure without a significant change in their lattice constants, while the crystallite size, grain size and number of unit cells in ZnO particle are increased. The residual stress is negative (compressive) and almost increases as Ni increases up to 0.10, but it is changed from negative to positive (tensile) at Ni = 0.20. The absorption and reflectance of UV spectra are increased as Ni increases up to 0.20. An absorption band centered at a wavelength of 552 nm is also observed and is gradually shifted by Ni towards longer wavelengths. Interestingly, two direct electronic transitions are found for all samples and two induced bandgaps which are decreased by Ni. While the other optical constants such as linear chi(1) and non-linear third-order susceptibilities chi(3), dispersion parameters (E-d, E-o), refractive indexes (n(o), n(2)), lattice dielectric constant epsilon(L), N/m*, optical and electrical conductivities (sigma(opt), sigma(ele)) are increased by Ni, the dissipation factor (tan delta) is decreased. Although some of the continuous peaks of lower PL intensities are recorded at UV band edges and slightly shifted to longer wave lengths (red shift) as Ni increases, strong UV emission peaks at about 390, 420 and 440 nm are recorded. Finally, the signature of a clear weak ferromagnetism ordering at room temperature, with evaluated magnetic parameters such as magnetization M-s, magnetic moments mu and magneto-crystalline anisotropy factor gamma, is recorded for Ni >= 0.05 doped samples.