Comparative Study of Ni- and Co-Substituted ZnO Nanoparticles: Synthesis, Optical, and Magnetic Properties

Abstract

International audienceNi- and Co-substituted ZnO nanoparticles were synthesized using forced hydrolysis of acetate metallic salts in a polyol medium. The X-ray diffraction patterns show a hexagonal wurtzite structure (space group P63mc). The characteristic absorption bands of UV-vis-IR spectra are correlated with the d-d transitions of tetrahedrally coordinated Co2+ and Ni2+ ions in octahedral and tetrahedral sites. The photoluminescence spectra exhibited a typical ZnO UV-exitonic emission band around 380 nm and a broad band between 400 and 500 nm that might be ascribed to the intrinsic defects in the ZnO material. The transmission electron microscopy displays spherical particles with a diameter between 20 and 30 nm. The magnetic measurements reveal that Zn1-xNixO and Zn1-xCoxO nanoparticles show, respectively, ferromagnetic and paramagnetic behavior at 5 K. Homogeneous distributions of Co and Ni ions in the particles observed by filter imaging analysis indicates that there is no evidence of Co or Ni metal throughout the powders

Effect of Ni-doping on the structural, optical and magnetic properties of ZnO nanoparticles by solvothermal method

“…Mn, Fe, Co, Ni) doped ZnO materials. Nickel doped ZnO diluted magnetic semiconductor with room temperature ferromagnetism in the form of thin films and nanocrystals has been studied [11][12][13][14]. Different methods such as thermal decomposition, sol-gel, hydrothermal and solvothermal method etc., have been used to synthesize the ZnO nanoparticles.…”

ZnO Nanoparticles Applied to Bioimaging and Drug Delivery

“…Doping ZnO nanoparticles with magnetic elements was suggested to obtain new binary probes with both fluorescent and magnetic functions, so that the labeled tissues deep within the animal body could be detected by MRI techniques. However, many ZnO nanoparticles doped with conventional magnetic elements, such as Fe, Co, Ni, and Mn, showed almost no luminescence in the visible region 37–42. One reason is that doping nanocrystals usually requires high temperature treatment, but under such conditions the defect concentration in ZnO nanoparticles will decrease and the defect‐related visible emission will be weakened.…”

Magnetic and optical studies of Fe and Co co-doped ZnO

“…Dietl et al reported ferromagnetism at room temperatue (RT-FM) for diluted magnetic semiconducting compounds, such as 3d ions M 2 +-substituted zinc oxide [2]. This class of materials is potentially interesting for spintronic devices, such as spin valves, magnetic sensors, spin light-emitting diodes, and non volatile memory [3]. Intrinsic Co-doped ZnO should be paramagnetic but room temperature ferromagnetism (RTFM)…”