Structural, optical, thermoelectrical, and magnetic study of Zn_1‐xCo_xO (0 ≤ x ≤ 0.10) nanocrystals

Abstract

In this work, we have prepared Co‐doped ZnO nanocomposites by zinc nitrate and cobalt sulfate as new precursors via the coprecipitation method and the samples were followed to identify the morphological, optical, structural, and magnetic properties. The XRD patterns revealed the crystalline nature of nanoparticles with hexagonal wurtzite structures, which meant that Co impurity did not disturb the structure of pure ZnO and the minimum crystallite size of nanoparticles was calculated to be around 37 nm. The XRD patterns also showed the lattice parameter increase owing to the incorporation of a Co dopant. The TEM results revealed the sphere‐like particles whose size varied between 56 and 88 nm in diameter at a 4% level of impurity. DRS analysis identified that the band gap energy decreased from 3.18 eV for the pure substance to 2.36 eV for the 10% impure substance. VSM analysis exhibited that the saturation magnetization value increased to 8.4 × 10−3 emu/g for the highest Co content of 10%, which indicated the ferromagnetic behavior of NPs.

Optical properties and complex refractive index of Co doped ZnO waveguide thin films elaborated by spray pyrolysis

“…In the region ranging from 500 to 750 nm we can clearly observe a decrease in the average transmittance from 84 to 57 % with the increase of cobalt concentration. The observed spectra were very similar to those obtained in the literature for Co doped ZnO thin films [21][22][23][24][25]. Due to the similar ionic radii of Zn +2 (0.60 Å) and…”

Progress on Transition Metal-Doped ZnO Nanoparticles and Its Application

“…A sructural study done by Akhtari et al 153 has shown a decrease in lattice parameters a and c with concentration (Figure 14). Co plays an important role in optoelectronic properties such as the dielectric constant, refractive index, absorption coefficient, relative transmittance and absorbance, and extinction coefficient.…”

“…The room temperature susceptibility was found to be in the range of 10 −4 emu g −1 when measured in a field of 1000 Oe for Co-doped ZnO, while for Mn-doped ZnO it comes in the range of only 10 −6 emug −1 . 153 The Cr-, Mn-, and Ni-doped nc-ZnO films show the well-defined ferromagnetic features at RT. The coercivity is 34, 56, and 54 Oe for ZnO:Cr, ZnO:Mn, and ZnO:Ni film, respectively.…”

“…Similarly, RT ferromagnetism for Mn-doped ZnO was also not observed for nanowires synthesized by high-pressure pulsed laser deposition and ZnO powders synthesized by the sol−gel process using ethanol as the solvent. 153 The magnetic ground state is also sensitive to the synthesis route. RT ferromagnetism is observed for thin films in the case of Mn doping, in cornlike Mn-doped ZnO nanorods, and in ZnO nanorods grown by chemical vapor deposition on sapphire and Si substrates.…”

Structural and optical study of Fe3+‐doped Al2O3 nanocrystals prepared by new sol gel precursors

“…Metal oxide semiconductors are widely used because of their excellent properties and numerous applications in optical and electronic fields . Aluminum oxide (Al 2 O 3 ) is an electric insulator with relatively high heat conductivity.…”