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Structural and magnetic studies on Co-Zn nanoferrite synthesized via sol-gel and combustion methods

Abstract

Co–Zn nanocrystalline ferrites with chemical composition Co0:5Zn0:5Fe2O4 were synthesized by sol-gel and combustion methods. The sol-gel method was carried out in two ways, i.e. based on chelating agents PVA and PEG of high and low molecular weights. In auto-combustion method, the ratio of citric acid to metal nitrate was taken as 1:1, while in sol-gel method the chelating agents were taken based on oxygen balance. All the three samples were studied by thermogravimetric and differential thermal analysis for the identification of phase formation and ferritization temperature. The synthesized samples were characterized by powder X-ray diffraction and FT-IR spectroscopy without any thermal treatment. The measured lattice constants and observed characteristic IR absorption bands of the three samples are in good agreement with the reported values showing the formation of a cubic spinel structure. The crystallite sizes of all samples were determined using high intensity peaks and W-H plot. Size-Strain Plot method was also implemented since two of the samples showed low crystallite sizes. The least crystallite size (5.5 nm) was observed for the sample CZVP while the highest (23.8 nm) was observed for the sample CZCA. Cation distribution was proposed based on calculated and observed intensity ratios of selected planes from X ray diffraction data. All structural parameters were presented using experimental lattice constant and oxygen positional parameter, and they correlated with FT-IR results. Magnetic measurements were carried out using vibrating sample magnetometer at room temperature to obtain the characteristic parameters such as saturation magnetization, coercivity, remanence, squareness ratio and Bohr magnetons. Among all, the sample synthesized via citric acid autocombustion method displayed a remarkably higher magnetization of 53 emu/g and the remaining two samples displayed low magnetization values owing to their smaller crystallite sizes.

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The structural studies of aluminosilicate gels and thin films synthesized by the sol-gel method using different Al2O3 and SiO2 precursors

Abstract

Aluminosilicate materials were obtained by sol-gel method, using different Al2O3 and SiO2 precursors in order to prepare sols based on water and organic solvents. As SiO2 precursors, Aerosil 200TM and tetraethoxysilane TEOS: Si(OC2H5)4 were applied, while DisperalTM and aluminium secondary butoxide ATSB: Al(OC4H9)3 were used for Al2O3 ones. Bulk samples were obtained by heating gels at 500 °C, 850 °C and at 1150 °C in air, while thin films were synthesized on carbon, steel and alundum (representing porous ceramics) substrates by the dip coating method. Thin films were annealed in air (steel and alundum) and in argon (carbon) at different temperatures, depending on the substrate type. The samples were synthesized as gels and coatings of the composition corresponding the that of 3Al2O3·2SiO2 mullite because of the specific valuable properties of this material. The structure of the annealed bulk samples and coatings was studied by FT-IR spectroscopy and XRD method (in standard and GID configurations). Additionally, the electron microscopy (SEM) together with EDS microanalysis were applied to describe the morphology and the chemical composition of thin films. The analysis of FT-IR spectra and X-ray diffraction patterns of bulk samples revealed the presence of γ-Al2O3 and δ-Al2O3 phases, together with the small amount of SiO2 in the particulate samples. This observation was confirmed by the bands due to vibrations of Al–O bonds occurring in γ-Al2O3 and δ-Al2O3 structures, in the range of 400 to 900 cm−1. The same phases (γ-Al2O3 and δ-Al2O) were observed in the deposited coatings, but the presence of particulate ones strongly depended on the type of Al2O3 and SiO2 precursor and on the heat treatment temperature. All thin films contained considerable amounts of amorphous phase.

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Application of Anaerobic Digestate as Inoculum for Treatment of the Plant-Derived Wastes: Case Study

,” Water Research , vol. 13, no. 6, pp. 485–492, Jan. 1979. https://doi.org/10.1016/0043-1354(79)90043-5 [21] M. Grube, J. G. Lin, P. H. Lee, and S. Kokorevicha, “Evaluation of sewage sludge-based compost by FT-IR spectroscopy,” Geoderma , vol. 130, no. 3–4, pp. 324–333, Feb. 2006. https://doi.org/10.1016/j.geoderma.2005.02.005 [22] M. Grube, I. Dimanta, M. Gavare, I. Strazdina, J. Liepins, T. Juhna, and U. Kalnenieks, “Hydrogen-producing Escherichia coli strains overexpressing lactose permease: FT-IR analysis of the lactose-induced stress

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Synthesis, growth and characterization of organic crystal triphenylmethane p-nitroaniline: a nonlinear optical crystal

References [1] CHEMLA D.S., ZYSS J., Nonlinear optical properties of organic molecules and crystals, Academic Press, New York, 1987. [2] PRASAD P.N., WILLIAMS D.J., Introduction to nonlinear optical effects in organic molecules and polymers, Wiley, New York, 1991. [3] HARI SINGH NALWA, SEIZO MIYATA, Nonlinear optics of organic molecules and polymers, CRC Press, Boca Raton, 1997. [4] MOHAN J., Organic Spectroscopy, principles and applications, Alpha Science International Ltd, Harrow, 2004

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Bioactive core material for porous load-bearing implants

composites of hydroxyapatite (HA) particles and poly L-lactide (PLLA). Part II: practical properties of miniscrews and miniplates. Biomaterials 22 (2001), 3197-3211. Ignjatović N., Savić V., Najman S., Plavsić M., Uskoković D.: A study of HAp/PLLA composite as a substitute for bone powder, using FT-IR spectroscopy. Biomaterials 22 (2001), 571-575. Shikinami Y., Okuno M.: Bioresorbable devices made of forged composites of hydroxyapatite (HA) particles and poly L-lactide (PLLA). Part I. Basic characteristics. Biomaterials

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Modification in surface properties of poly-allyl-diglycol-carbonate (CR-39) implanted by Au+ ions at different fluences

in the range from 5 × 10 13 ions/cm 2 to 5 × 10 15 ions/cm 2 . The structural and chemical alterations in CR-39 induced by ion implantation were analyzed by Raman and Fourier transform infrared (FT-IR) spectroscopy. The changes produced in the optical properties of implanted CR-39 were estimated using UV-Vis spectroscopy. The effect of varying fluence of metal ions on the electrical conductivity of implanted samples was explored. The examination of surface morphology of Au + ion implanted CR-39 was carried out by atomic force microscopy. The mechanism of

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Influence of zinc concentration on band gap and sub-band gap absorption on ZnO nanocrystalline thin films sol-gel grown

. 3.3 FT-IR analysis Fig. 5 shows FT-IR spectra of ZnO thin films with different zinc concentrations. The characteristic ZnO absorption bands are centered at 488 cm −1 . However, a lower frequency peak of low intensity at ~759 cm −1 , related to the ZnO stretching mode, is observed in the present spectra. We observe various other peaks due to the solvent effects. The absorption bands are centered at 1423 cm −1 due to the O–H bending of the hydroxyl group. The absorption peaks at 1581 cm −1 are due to the acetate group (CH 3 COO − ). From Fig. 5 , it can be

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Effect of lead salts on phase, morphologies and photoluminescence of nanocrystalline PbMoO4 and PbWO4 synthesized by microwave radiation

times, and dried at 80 °C for 24 h. The products were characterized by X-ray diffraction (XRD, Siemens D500) in the range of 2θ scanning angle of 15° to 60°, using CuKα radiation with graphite monochrome and a Ni filter, Fourier transform infrared spectroscopy (FT-IR, Bruker Tensor 27, better than 1 cm −1 ) operating in the range of 4000 cm −1 to 400 cm −1 with KBr as a diluting agent, Raman spectroscopy (T64000 HORIBA Jobin Yvon with high spectral resolution) using a 50 mW and 514.5 nm wavelength Ar green laser, scanning electron microscopy (SEM, JEOL JSM-6335F

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Novel and facile synthesis of transparent-monolithic TiO2 gels by sol-gel method based on an esterification reaction

white precipitate was formed after 30 min. The precipitate so obtained was aged overnight at room temperature to ensure conclusion of the hydrolysis. Fourier transform infrared (FT-IR) spectroscopy study was carried out with a Nicolet Impact 400 spectrometer in the 4000 cm -1 to 400 cm -1 wavenumber range using a spectral resolution of 4 cm -1 and a scan number of 40. In case of samples in a powder form, the pellets were made by adding 300 mg of KBr to 1 mg sample (0.3 %). This technique can, however, generate a phenomenon of diffusion greater for high values of

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One step paired electrochemical synthesis of iron and iron oxide nanoparticles

, therefore decreases the size of nanoparticles [ 14 ]. In the present work, two widely used nanoparticles of iron and iron oxide were obtained at the same time by the pulsed current electrochemical method using a membrane divided electrochemical cell and iron (II) sulfate aqueous solution as a starting material. The composition, size and morphology of the synthesized samples were characterized by FT-IR spectroscopy, XRD, SEM, TEM and VSM studies. The method has been found to be simpler, efficient, clean and energy saving, which could have a potential for industrial

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