Nano-sized copper doped zinc ferrite powders, Zn1-xCu xFe2O4 (x = 0.0, 0.1, 0.2, 0.3, 0.4 and 0.5) were synthesized by microwave combustion method. The structural, morphological and magnetic properties of the products were determined and characterized in detail by X-ray diffraction (XRD), high resolution scanning electron microscopy (HR-SEM), energy dispersive X-ray spectroscopy (EDX) and vibrating sample magnetometer (VSM). X-ray analysis showed that all compositions crystallize with a cubic spinel-type structure. The lattice parameter decreased from 8.443 to 8.413 Å with increasing Cu content. The average crystallite size was found in the range of 41.20-45.84 nm. Magnetic measurements revealed that for lower Cu concentration (x ≤ 0.2), the system shows a superparamagnetic behavior whereas for higher concentration (x ≥ 0.2), it becomes ferromagnetic. It has been explained in terms of random distribution of Zn2+ and Fe 3+ ions at tetrahedral [A] and octahedral [B] sites. The saturation magnetization (Ms) varies considerably with Cu content to reach a maximum value for Cu0.5Zn0.5Fe2O4 composition, i.e. 58.58 emu/g. The high saturation magnetization of these samples suggests that this method is suitable for preparing high quality nanoparticles for magnetic applications. The broadband visible emission is observed in the entire photoluminescence (PL) spectrum and the estimated energy band gap is about 2.1 eV. The composition with x = 0.5 showed the highest intensity and was explained on the basis of disordered cluster model. © 2012 Elsevier B.V. All rights reserved.

John Kennedy L

Physics

School of Advanced Sciences

Chennai Campus

Manikandan A

Judith Vijaya J

Bououdina M.

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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&nbsp;

VIT University

Journal of Molecular Structure

Recent developments show that the exceptional physical, optical, magnetic, and electrical properties of spinel ferrite (SF) nanomaterials have now attracted the attention as high-density data storage materials, catalysts, gas sensors, rechargeable lithium batteries, information storage systems, magnetic bulk cores, adsorbents, magnetic fluids, microwave absorbers, and medical diagnostics. The aim of this review consists on an overview on the methods of preparation, the crystal structure and application of SFs used in technology for the design of new materials and devices. The chapter begins with a review of the different synthesis methods commonly used for the preparation of SFs. Then, the structural features of spinel unit cell, crystal chemical parameters, and extrinsic magnetic and optical properties are described in this chapter. Since the magnetism of SFs depends not only on particle chemistry and phase but also on the particle size and environment, the role of cationic distribution and ion exchange interaction are explored in determining the magnetic properties of the system. In addition, the potential applications of SFs in different fields of technology are also discussed. © Springer International Publishing AG 2017.

Springer Proceedings in Physics Nanophysics, Nanomaterials, Interface Studies, and Applications

Spinel Ferrite Nanoparticles: Synthesis, Crystal Structure, Properties, and Perspective Applications

Sphere/rod-like α-Fe2O3 nanostructure were successfully synthesized by simple surfactant-free precipitation route. The as-prepared samples were characterized by X-ray powder diffraction (XRD) to determine the phase purity and the crystal structure. The lattice parameter and crystallite size of the samples have been calculated from the Rietveld analysis. The crystallite size has been compared by Scherrer's formula and Rietveld method and both method showed increase of the grain size with the increase of the calcined temperature. The crystallite size was in the range of 5–30 nm. The high resolution scanning electron microscopy (HR-SEM) analysis of the samples shows that the morphology of the nanostructures changed from nanospheres into nanorods and it was confirmed by high resolution transmission electron microscopy (HR-TEM). Energy dispersive X-ray (EDX) analysis reveals the presence of O and Fe elements only. The optical properties of the as-prepared nanostructures were determined by photoluminescence (PL) spectra. The band gap energy was investigated by UV-Visible diffuse reflectance spectra (DRS) and calculated by means of the Kubelka-Munk method. The band gap values are decreased from 2.26 eV to 2.17 eV as the temperature increased from 300 °C to 400 °C with increasing the crystallite size. A Vibrating Sample Magnetometer (VSM) was used to study the magnetic properties of iron oxide (α-Fe2O3) nanostructures. Magnetic hysteresis (M–H) loops revealed that the as-prepared α-Fe2O3 samples displayed ferromagnetic behavior.

Journal of Nanoscience and Nanotechnology

Synthesis of α-Fe2O3 Sphere/Rod-Like Nanostructure via Simple Surfactant-Free Precipitation Route: Optical Properties and Formation Mechanism

Iron oxide (Fe3O4) nanoparticles were synthesized by a facile microwave combustion method. X-ray diffraction and energy dispersive X-ray spectroscopy results showed that the as-prepared product was pure Fe3O4 without any impurity. The mechanism for the formation of Fe3O4 by microwave combustion method is also discussed. Microwave combustion produced sufficient energy for the formation of Fe3O4, because of its homogeneous distribution within the raw materials. This results in the formation of nanoparticles, early phase formation and different morphologies within few minutes. Magnetic analysis revealed that the Fe3O4 nanoparticles had ferromagnetic behavior at room temperature with saturation magnetization of 66.12 emu/g. © 2013 The Korean Society of Industrial and Engineering Chemistry.

Journal of Industrial and Engineering Chemistry

Structural, optical and magnetic properties of Fe3O4 nanoparticles prepared by a facile microwave combustion method

The present study reports a green chemistry approach for the biosynthesis of nano-zinc aluminate by a microwave method using high purity metal nitrates and aloe vera plant extract. Aloe vera extract simplifies the process and provides an alternative process for a simple and economical synthesis of nanocrystalline zinc aluminate. It is prepared by conventional and microwave method by with and without using the plant extract for comparison purpose. The obtained nanomaterials were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), high resolution scanning electron microscopy (HR-SEM), energy dispersive X-ray analysis (EDX), high resolution transmission electron microscopy (HR-TEM) diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) spectroscopy. The XRD confirmed the formation of cubic structure of zinc aluminate. The formation of zinc aluminate phase is also confirmed by FT-IR. The change in morphology from nanorods to nanosheets from the conventional method to microwave method is clearly shown by HR-SEM. The optical properties were determined by DRS and PL spectra. © 2013 The Society of Powder Technology Japan. Published by Elsevier B.V.

Advanced Powder Technology

A new approach: Synthesis, characterization and optical studies of nano-zinc aluminate

Spinel zinc ferrite (Zn1-xCoxFe2O 4) nanoparticles with various particle sizes were prepared by the microwave combustion method using urea as a fuel. The composites were prepared with the addition of cobalt at different molar ratios (x=0.0 to 0.5) to ZnFe2O4. The obtained spinel ferrites were characterized by X-ray powder diffraction (XRD) and their mean grain size and morphology were determined by the high resolution scanning electron microscopy (HR-SEM). The magnetic properties of the synthesized ferrites were investigated using room temperature vibrating sample magnetometer (VSM) and their hysteresis loops were obtained. The optical reflectance and photoluminescence (PL) emissions were determined by UV-visible diffuse reflectance spectra (DRS) and PL spectra respectively. The formation of single cubic spinel phase was confirmed by XRD and Rietveld analysis with an average crystallite size is in the range of 43-49 nm. The broadband visible emission band is observed in the entire PL spectrum and the estimated energy band gap is about 2.1 eV. The variation of saturation magnetization (Ms) value of the samples was studied. The prepared lower compositions (0.0, 0.1 and 0.2) show a superparamagnetic behavior and the higher compositions (0.3, 0.4 and 0.5) show a ferromagnetic behavior with hysteresis and that the Ms increases with increasing Co content to reach a maximum value of 65.20 emu/g for Zn0.5Co0.5Fe 2O4. The relatively high Ms of the samples suggests that this method is suitable for preparing high-quality nanocrystalline magnetic ferrites for practical applications. Different mechanisms to explain the obtained results and the correlation between magnetism and structure are discussed. © 2013 Elsevier B.V. All rights reserved.

Journal of Magnetism and Magnetic Materials

Synthesis, optical and magnetic properties of pure and Co-doped ZnFe2O4 nanoparticles by microwave combustion method

A simple, low temperature co-precipitation method was developed to synthesize ZnO nanomaterials with different morphologies such as nanoflakes, spherical nanoparticles (SNPs), and nanorods. The concentration of the capping agent, Triton X-100, is a key factor in the morphological control of ZnO nanostructures. The formation of different morphologies of ZnO was confirmed by HR-SEM and HR-TEM. XRD data showed the formation of single-phase ZnO with the wurtzite crystal structure. The influence of La contents on the structure, morphology, absorption, emission, and photocatalytic activity of ZnO SNPs was investigated systematically. The influence of the ZnO morphologies on the photocatalytic degradation (PCD) of Bisphenol A (BPA) as a model reaction is evaluated and discussed in terms of surface area, crystal growth habits, particle size, and oxygen defects. The results indicated that the particle size is an important factor for the enhancement of PCD. Furthermore, the effect of different photocatalytic reaction parameters on the resulting PCD efficiency of ZnO SNPs was investigated. © 2013 Elsevier Inc.

Journal	Data powered by TypesetJournal of Molecular Structure
Publisher	Data powered by TypesetElsevier BV
ISSN	0022-2860
Open Access	No