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Glycine assisted self-combustion method resulted in fabrication of cobalt-manganese ferrite substituted by zinc (Zn) element. The as- synthesized Zn substituted Co- Mn ferrite was subjected to heat treatment at 600 oC and 800 oC for 2h. Effects of heat treatment on the structural, morphological, surface and magnetic properties of ZnCoMn ferrite were studied. These properties were characterized by using various techniques including TGA-DTGA, FTIR, XRD, SEM, EDX, TEM and VSM. The results showed that the used preparation route led to the formation of nano crystalline Zn0.2Co0.4Mn0.4Fe2O4 particle with cubic spinel type structure. The crystallinity of this ferrite increases as the heat treatment increases. However, the preparation method resulted to the creation of spongy, fluffy, foamy and fragile material with cubic type structure with some agglomerations. Increasing the calcination temperature from 600 oC to 800 oC, led to a decrease in the surface area (39.4 %) of the as- synthesized ferrite. This treatment causes an increase in the magnetization(40.3 %) of this ferrite. The heat treatment that led to various changes in the different properties of the manufactured ferrite was discussed.

Series of CuO/CuCo2O4 composites were prepared by using the combustion method followed by heating at 750oC with different molar ratios of Cu/Co. Characterization of different composites is systematically investigated with various analytical techniques. X-ray diffraction patterns and Fourier-transform infrared spectroscopy indicate the growth of well crystalline CuCo2O4 nanoparticles with a cubic spinel structure. Images of transmission electron microscope and scanning electron microscope show a uniform particle distribution. From UV-visible spectra, the calculated optical band gaps of various solids were ranged between 1.2 and 1.8 eV. Electrical properties were measured at temperature ranged from 303 to 463 K in a frequency range from 102 to 106 Hz. The AC conductivity satisfied the Jonscher equation, especially at high frequency. The obtained data of conductivity and dielectric constant indicated that the prepared samples behave as semiconductor materials. Finally, it can be concluded that the CuO/CuCo2O4 composite showed attractive multi-functional features for electrical applications.

This study is the first attempt to large-scale energy-efficient production of nanomagnetic Ni/NiO composites by using the autocombustion based on leaves or extract of corchorus olitorius. The as synthesized product can be characterized by using XRD, SEM, TEM and EDX techniques. The results confirm that the as synthesized materials consisted entirely of well crystalline Ni and NiO phases. The crystallinity of both Ni and NiO enhanced by increasing amount of the corchorus olitorius. However, the corchorus olitorius - treatment resulted in an increase in the crystallite size and lattice constant. The SEM analysis confirms formation of fragile, fluffy and spongy networks. The average of grain size for the as prepared particles was found to be 45 nm in agreement with the trend of the crystallite size calculated by using XRD technique. Furthermore, changing of nature and content of the corchorus olitorius brought about progressive modifications in the magnetic properties, namely, Ms, Mr, Mr/Ms, Hc and Ka, of the fabricated Ni/NiO nanocomposite according to the structural, morphological as well as microstructural variation. The saturation magnetization (Ms) of the sample with corchorus olitorius leaves was found to be 0.2383 emu/g while the Ms with corchorus olitorius extract was found to 6.977 emu/g. This was discussed in the light of finite size, surface and interface effects. Thus, we unveil a new approach for incandescent combustion synthesis via an innate approach for corchorus olitorius leaves in the directly fabrication for different nanocomposites.

The biomimetic synthesis of a ZnO/C nanocomposite has been achieved using the egg white-assisted self-combustion method. The characterization of this composite has been carried out using different techniques, such as XRD, FTIR, Raman, SEM/EDS and TEM. A comparative study was conducted between ZnO in the form of this composite and pristine ZnO, which was prepared via the same procedures but without the egg white. The resulting ZnO had a hexagonal structure, similar to wurtzite, with a P63mc space group. When this egg white method was used to produce a ZnO-based material, a ZnO/C nanocomposite was developed, and the ZnO's crystallite size was significantly decreased. The structural properties—including the unit cell volume, strain, atom displacement and dislocation density—of this ZnO crystal are increased as a result of the presence of a C atom. On the other hand, the length of the Zn–O bond is reduced by the presence of the C atom. Results derived from a combination of Raman, FTIR, and EDS demonstrate that the carbonaceous layers and ZnO nanoparticles were integrated with a close interfacial contact. The preparation method used here brought about obvious changes in the morphological and magnetic behaviors of the as-prepared materials. Using a small amount of egg white resulted in the transformation of the particle's shape from a hexagonal cone-type structure to an ellipsoidal structure. Based on an analysis of diffuse reflectance, the ZnO and ZnO/C band gap values were revealed using UV–VIS spectra. ZnO and ZnO/C exhibit band gap energies of 3.09 and 2.60 eV, respectively. A phase transition from weakly ferromagnetic to completely diamagnetic magnetic was discovered. [ABSTRACT FROM AUTHOR]

A series of virgin and lithia-doped Ni ferrites was synthesized using egg-white-mediated combustion. Characterization of the investigated ferrites was performed using several techniques, specifically, X-ray Powder Diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and High-resolution transmission electron microscopy (HRTEM). XRD-based structural parameters were determined. A closer look at these characteristics reveals that lithia doping enhanced the nickel ferrite lattice constant (a), unit cell volume (V), stress (ε), microstrain (σ), and dislocation density (δ). It also enhanced the separation between magnetic ions (LA and LB), ionic radii (rA, rB), and bond lengths (A-O and B-O) between tetrahedral (A) and octahedral (B) locations. Furthermore, it enhanced the X-ray density (Dx) and crystallite size (d) of random spinel nickel ferrite displaying opposing patterns of behavior. FTIR-based functional groups of random spinel nickel ferrite were determined. HRTEM-based morphological properties of the synthesized ferrite were investigated. These characteristics of NiFe2O4 particles, such as their size, shape, and crystallinity, demonstrate that these manufactured particles are present at the nanoscale and that lithia doping caused shape modification of the particles. Additionally, the prepared ferrite's surface area and total pore volume marginally increased after being treated with lithia, depending on the visibility of the grain boundaries. Last, but not least, as the dopant content was increased through a variety of methods, the magnetization of virgin nickel ferrite fell with a corresponding increase in coercivity. Uniaxial anisotropy, rather than cubic anisotropy, and antisite and cation excess defects developed in virgin and lithia-doped nickel ferrites because the squareness ratio (Mr/Ms) was less than 0.5. Small squareness values strongly recommend using the assessed ferrites in high-frequency applications. [ABSTRACT FROM AUTHOR]

Series of CuO/CuCo2O4 composites were prepared by using the combustion method followed by heating at 750oC with different molar ratios of Cu/Co. Characterization of different composites is systematically investigated with various analytical techniques. X-ray diffraction patterns and Fourier-transform infrared spectroscopy indicate the growth of well crystalline CuCo2O4 nanoparticles with a cubic spinel structure. Images of transmission electron microscope and scanning electron microscope show a uniform particle distribution. From UV-visible spectra, the calculated optical band gaps of various solids were ranged between 1.2 and 1.8 eV. Electrical properties were measured at temperature ranged from 303 to 463 K in a frequency range from 102 to 106 Hz. The AC conductivity satisfied the Jonscher equation, especially at high frequency. The obtained data of conductivity and dielectric constant indicated that the prepared samples behave as semiconductor materials. Finally, it can be concluded that the CuO/CuCo2O4 composite showed attractive multi-functional features for electrical applications. [ABSTRACT FROM AUTHOR]

Egg white-induced auto combustion has been used to synthesize undoped and Fe-doped CuO/Cu2O/Cu4O3 nanocomposites in a soft, secure, and one-pot procedure. X-ray powder diffraction (XRD) and Fourier transform infrared (FTIR) investigations have been used to identify functional groups and the structural properties of crystalline phases present in the as-synthesized composites. Scanning Electron Microscopy/Energy Dispersive Spectrometry (SEM/EDS) elemental mapping analyses and Transmission Electron Microscopy (TEM) techniques were used to explore the morphological and compositional properties of these composites. N2-adsorption/desorption isotherm models have been used to examine the surface variables of the as-prepared systems. Based on the Vibrating Sample Magnetometer (VSM) technique, the magnetic properties of various copper-based nanocomposites were detected due to being Fe-doped. XRD results showed that the undoped system was composed of CuO as a major phase with Cu2O and Cu4O3 as second phases that gradually disappeared by increasing the dopant content. The crystalline phase's crystallographic properties were determined. The average particle size was reduced when the synthesized systems were doped with Fe. The construction of porous and polycrystalline nanocomposites involving Cu, Fe, O, and C components was confirmed by SEM/EDS and TEM measurements. In terms of the increase in magnetization of the as-manufactured nanocomposites due to Fe-doping, oxygen vacancies at the surface/or interfacial of nanoparticles, while also domain wall pinning mechanisms, were investigated. Finally, employing the investigated production process, Fe doping of CuO/Cu2O/Cu4O3 nanocomposite resulted in the development of a single phase (CuO) exhibiting "pinned" type magnetization. This is the first publication to show that CuO/Cu2O/Cu4O3. [ABSTRACT FROM AUTHOR]

The preparation of copper manganite (hopcalite, Cu1.5Mn1.5O4), as a single phase, was achieved by using a sustainable method of green synthesis. This method is based on the replacement of the conventional "brute force" ceramic preparation by the recent "soft force" green synthesis via the egg white assisted one-step method. In other words, we present a facile and rapid methodology to prepare the nanocrystalline Cu1.5Mn1.5O4 spinel as a single phase, compared to our previous work using ceramic and glycine-assisted combustion methods. The as-synthesized copper manganite was characterized using X-ray diffraction (XRD), Fourier-transform infrared (FTIR), energy-dispersive spectroscopy (EDS), and scanning electron microscope (SEM). We used a vibrating sample magnetometer to determine the magnetic properties of the prepared sample (VSM). XRD, FTIR, SEM, EDS and transmittance electron micrograph (TEM) resulted in synthesis of a successful cubic spinel Cu1.5Mn1.5O4 system with a sponge crystal structure. The particles of the prepared materials are polycrystalline in their nature and the sizes ranged between 50 and 100 nm. The magnetic measurement demonstrated that the generated nanostructure has been found to exhibit ferromagnetism at room temperature with an optimum saturation magnetization value (0.2944 emu/g). [ABSTRACT FROM AUTHOR]

A series of copper-based systems containing two different nanocomposites (Cu2O/CuO and Cu2O/Cu) was synthesized by the egg white assisted auto-combustion route. This method was distinguished by the simplicity of its steps, low cost, one-pot synthesis process at low temperature and, short time. The characterization of the as prepared nanocomposites was carried out by using X-ray diffraction (XRD), Fourier-transform infrared (FTIR), Scanning electron microscope (SEM) and transmission electron micrograph (TEM), Energy dispersive spectrometry (EDS) techniques. Surface and magnetic properties of the obtained systems were determined by using N2 adsorption/desorption isotherms at 77 K and the vibrating sample magnetometer (VSM) technique. XRD results confirmed the formation of Cu2O/CuO and Cu2O/Cu nanocomposites with different ratios of well crystalline CuO, Cu2O, and Cu phases. FTIR results of the combusted product displays the presence of both CuO and Cu2O, respectively. SEM/EDS and TEM results confirm the formation of a porous nanocomposite containing Cu, O, and C elements. The change in concentration of the oxygen vacancies at the surface or interface of both Cu2O/CuO and Cu2O/Cu nanoparticles resulted in different changes in their magnetization. Based on this study, it is possible to obtain nanocomposite-based copper with multiple valances by a simple and inexpensive route which can be suitable for the fabrication of different transition metal composites. [ABSTRACT FROM AUTHOR]