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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 (Zn1−(x+y)MnxCryO, 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 Zn0.85Mn0.075Cr0.075O 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.

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Heat resisting and water-soluble chocolate polyesters containing azomethine group

Abstract

In this study, soluble in water poly(azomethine-ester)s (PAEs) were synthesized via elimination reactions of aromatic dihydroxy compounds containing imine bonding with terephthaloyl chloride. The structures of Schiff bases (SBs) and PAEs containing different aliphatic chains were confirmed by FT-IR, 1H-NMR, 13C-NMR and UV-Vis analyses. Physicochemical properties of the new polymers were characterized. Thermal properties of the compounds were investigated by TGA-DTA, DMA and DSC. According to TGA measurements, the starting degradation temperatures (Ton) of P-1, P-2, P-3, and P-4 poly(azomethine-ester)s were found as 255 °C, 232 °C, 222 °C, and 221 °C, respectively. The starting degradation temperatures of the poly(azomethine-ester)s were higher than their Schiff base compounds. According to dynamical mechanical analysis (DMA) measurements, glass transition temperature (Tg) of P-1, P-2, P-3, and P-4 poly(azomethine-ester)s were found as 95 °C, 138 °C, 140 °C, and 145 °C, respectively. The morphological and topographic properties of the PAEs containing azomethine linkage in the main chain were investigated by FE-SEM and AFM, respectively. The molecular mass distributions of PAEs were determined by gel permeation chromatography (GPC). Electrochemical (E′g) and optical band gap (Eopt g ) values of the prepared SBs and PAEs were calculated from cyclic voltammetry (CV) and UV-Vis analyses. The electrochemical band gap (E′g) values of P-1, P-2, P-3 and P-4 were found as 2.44 eV, 2.41 eV, 2.39 eV and 2.39 eV, respectively, from the cyclic voltammetry.

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Photocrosslinkable polymer based on 4-(3-(2,4-dichlorophenyl)-3-oxoprop-1-enyl) phenylacrylate: synthesis, reactivity ratio, and crosslinking studies

received from SD Fine Chemicals. Ethyl methyl ketone (MEK), acrylic acid (AA) and hydroxyethyl acrylate (HEA) were used as received from Merck. Acryloyl chloride was prepared using commonly known procedure [18] . ALPHA BRUKER FT-IR spectrophotometer was used for recording IR spectrum and the spectra were recorded using KBr pellet method. 1 H NMR spectra of the samples were run on a Bruker FT-NMR spectrophotometer operating at 500 MHz using CDCl 3 or DMSO-d 6 as a solvent and tetramethyl silane (TMS) as an internal reference. UV absorption measurements were recorded

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Synthesis of SiC nanowhiskers from graphite and silica by microwave heating

. 2.3 Characterization of SiCNWs After the microwave heating was done, the samples were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy spectroscopy (EDX), photoluminescence spectroscopy (PL), Fourier transform infrared spectroscopy (FT-IR) and thermo-gravimetric analysis (TGA). The morphologies of the samples were observed by using FESEM model Nova Nano 450 at magnification of 200,000× and accelerating voltage of 5 kV while EDX (EDX OXFORD FM29142) was used to determine the

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Synthesis, investigation on structural and electrical properties of cobalt doped Mn–Zn ferrite nanocrystalline powders

examined using BRUKER-binary V2 (RAW) powder diffractometer using CuKα (λ = 1.54060 Å) radiation. The surface morphologies of the nanopowders were measured with a scanning electron microscope. For the electrical measurements, the powder sample was pelletized at a pressure of 300 kg/cm2 to yield a pellet of 10 mm diameter and 2 mm thickness. The dielectric constant and loss tangent of these powders were measured by using LCR HiTESTER (HiOKI 3532-50). The crystalline structure of CMZF nanopowders was determined by using FT-IR spectroscopy. 3 Results and

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Optimized geometry, vibration (IR and Raman) spectra and nonlinear optical activity of p-nitroanilinium perchlorate molecule: A theoretical study

1.087 2.338 3.393 163.2 3.2 Vibrational assignments The IR and Raman spectra for PNAPC molecule have been simulated by using B3LYP and HSEH1PBE levels and the obtained results are given in Fig. 2 and Fig. 3 as compared with FT-IR and FT-Raman results [ 8 ]. The calculated vibration frequencies, the percentage of relative contribution of various internal co-ordinates and approximate descriptions of normal modes are listed in Table 3 . Frequency calculations at the same levels of theory revealed no imaginary frequencies, indicating that an

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Characterization of NiO–Al2O3 composite and its conductivity in biogas for solid oxide fuel cell

.67 eV signify that a less quantity of hydrogen is available. Nonetheless, propensity of CO 2 cracking may also be the reason of this lower conductivity. The conductivity and activation energy values in different atmospheres are tabulated in Table 4 . Table 4 DC conductivity and activation energy values in different atmospheres. Materials Atmosphere Conductivity [S/cm] × 10–3 Activation energy [eV] 400 °C to 610 °C NiO–Al 2 O 3 Air Biogas Hydrogen 0.97 3.2 4.3 0.88 0.67 0.23 The FT-IR spectra of NiO–Al 2 O 3 exposed

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Morphologies of nanostructured bismuth sulphide and Mn (II) doped bismuth sulphide nanoparticles: characterization and application

nanoparticles using a model JSM-5610 LV attached to scanning electron microscope (SEM). PerkinElmer Optima 4300 DV ICP-OES was used to analyze the constituents present in traces. FT-IR spectra were recorded for KBr pellet on the PerkinElmer Spectrum RX1 model in the range of 4000 cm −1 to 400 cm −1 . Doped and undoped Bi 2 S 3 nanoparticles catalyzed decolorization of methyl violet dye and the redox reaction of Fe ( CN ) 6 3 − ${\rm{Fe}}\left( {{\rm{CN}}} \right)_6^{3 - }$ and S 2 O 3 2 − ${{\rm{S}}_2}{\rm{O}}_3^{2 - }$ were monitored by PerkinElmer LAMBDA 35 UV

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Structural, optical and dielectric studies of lithium sulphate monohydrate single crystals

hydrogen-containing atmospheres [27] . Crystalline materials in which the structural arrangement allows the motion of alkali ions along specific crystallographic axes has been a prime focus of investigations. In the present work, the anomalous dielectric behavior of LSMH crystals has been reported. It was observed that AC conductivity of the present crystal system is controlled by hopping mechanism. The growth aspect and the characterization studies, such as SXRD, UV-Vis, FT-IR, TGA/DTG, and microhardness of LSMH single crystals have been presented. Some numerical

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Structural and electrochemical investigation of waste newspaper based electrodes for supercapacitor applications

ranging from 10° to 80° using CuKα radiation at a wavelength of λ = 1.540 Å. The other experimental conditions included 1/2° divergence slits, a 5-s residence time at each step and intensity measurements in counts. 2.3 FT-IR studies A Perkin Elmer infrared spectrometer was used for the investigation of surface functional groups of the porous carbon. The carbon samples were mixed with KBr of spectroscopic grade and shaped into pellets at a pressure of about 1 MPa. The pellets were about 10 mm in diameter and 1 mm in thickness. The samples were scanned in the

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