Structural optical and magnetic properties of transition metal doped ZnO magnetic nanoparticles synthesized by sol-gel auto-combustion method

Abstract

Transition metals, such as chromium (Cr) and manganese (Mn) doped zinc oxide (ZnO) magnetic nanoparticles, were synthesized via sole gel auto-combustion method. The prepared magnetic (Zn 1−(x+y) Mn x Cr y O, where x, y = 0, 0.02, 0.075) nanoparticles were calcined in an oven at 6000°C for 2 hours. The morphologies of the nanoparticles were investigated using different techniques. X-ray diffraction (XRD) analysis revealed that the hexagonal wurtzite structure of the synthesized nanoparticles was unaffected by doping concentration. The crystallite size measured by Scherrer formula was in the range of 32 nm to 38 nm at different doping concentrations. Nanosized particles with well-defined boundaries were observed using a field emission scanning electron microscopy (FE-SEM). Fourier transform infrared (FT-IR) spectra showed a wide absorption band around 1589 cm −1 in all the samples, corresponding to the stretching vibration of zinc and oxygen Zn-O bond. A blue shift in optical band gaps from 3.20 eV for ZnO to 3.08 eV for Zn 0.85 Mn 0.075 Cr 0.075 O nanoparticles was observed in diffuse reflectance spectra, which was attributed to the sp-d exchange interactions. The field-dependent magnetization M-H loops were measured using vibrating sample magnetometer (VSM). The VSM results revealed diamagnetic behavior of the ZnO nanoparticles which changed into ferromagnetic, depending on the doping concentration and particle size. The compositions of Zn, Cr, Mn and O in the prepared samples were confirmed by using the energy dispersive X-ray spectroscopy (EDX). Our results provided an interesting route to improve magnetic properties of ZnO nanoparticles, which may get significant attention for the fabrication of magnetic semiconductors.

Determination of Blood Calcium and Lead Concentrations in Osteoporotic and Osteopenic Patients in Pakistan

“…The correlation of Ca depletion and Pb enhancement may be attributed to the fact that Pb affects PTH and vitamin D activation in the kidney, and interferes with Ca absorption in the gut and impaired reabsorption of Ca in the renal tubules. , Experimental studies in bone culture systems indicate a direct effect of Pb on bone cells, causing both decreased bone formation and increased bone resorption. , …”

“…40,41 Experimental studies in bone culture systems indicate a direct effect of Pb on bone cells, causing both decreased bone formation and increased bone resorption. 42,43…”

First-Principles Calculations of the Electronic Structure and Optical Properties of Yttrium-Doped ZnO Monolayer with Vacancy

“…To enhance the photocatalytic efficiency, various synthesis methods and surface modifications (doping, composite, and deposition) have been adopted to change the crystal structure, size, morphology, and bandgap [13]. Metal doping can effectively promote the visible light harvesting ability of catalysts [14][15][16][17][18][19][20]. Yttrium (Y) is an environmentally-friendly and abundant rare earth (RE) element [21].…”

Investigation on microstructure, energy gap, photoluminescence and magnetic studies of Co and Cu in situ doped ZnO nanostructures

“…Table 2 illustrates the modi cation in lattice constants such as inter-planar distance 'd', 'a' and 'c' values, c/a ratio and volume per unit cell of Co, Cu doped ZnO with different Cu levels between 0% and 4%. The lattice parameter 'd' is obtained from Bragg's equation, 2d sin θ = nλ where 'q' is the angle of diffraction [59]. The lattice parameters 'a' and 'c' have been derived with the help of the lattice relation [60], 1/d 2 = 4/3 ((h 2 +hk+k 2 ) /a 2 ) + l 2 /c 2 and the volume per unit cell is obtained from the relation [61], volume (V) = 0.866 x a 2 x c. The change in 'd' value and lattice parameters is depending on doping elements, the defects induced by dopant, the difference in ionic radii and the induced strain or stress by doping element [62].…”