Impact of doping Gd3+rare earth ion on structural, magnetic, and optical properties of cobalt and nickel ferrite nanomaterials
TL;DR: In this article, the impact of Gd rare earth ion on structural, magnetic, and optical properties of Ni and Co spinel ferrite nanomaterial prepared by low-cost sol-gel method was studied.
Abstract: The impact of Gd rare earth ion on structural, magnetic, and optical properties of Ni and Co spinel ferrite nanomaterial prepared by low-cost sol–gel method has been studied in this research. The XRD measurement confirms the pure phase formation having crystallite size between 15.61–23.49 and 12.01–30.95 nm for Gd3+substituted CoFe2O4 and NiFe2O4, respectively. A slight decrement in crystallite size was found due to large size ion of rare earth elements. The lattice constants of CoFe2O4 materials displayed a decrease from 8.4477 to 8.3635 A and an increase from 8.3565 to 8.3968 A in NiFe2O4 materials, prepared at the same temperature. The molecular bonds between 469 and 3453 cm−1 were examined by FTIR spectroscopy. The direct bandgap (Eg) of CoFe2O4 and NiFe2O4 was between 1.63–2.41 and 1.61–1.66 eV, respectively, by UV–Visible spectroscopy. The room temperature PL studies (200 nm excitation) revealed a dominant blue emission and a weak green emission. The particle size of CoFe2O4 and NiFe2O4 was found 34 and 41.58 nm, respectively, by HRTEM which is close to the result obtained by XRD analysis. The coercivity (Hc) of pure CoFe2O4 and NiFe2O4displayed the magnitude of 1452.41 and 191.49 Oe, respectively. The saturation magnetization (Ms) was found between 30.59–57.84 and 23.99–42.11 emu/g for CoFe2O4 and NiFe2O4. The tuned optical and magnetic behavior could make them applicable in magneto-optical devices, water purification and other related uses.
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TL;DR: In this paper , a ternary nanocomposite was synthesized by a simple in situ reduction using a two-step approach and the structural and morphological properties were studied by UV-Vis spectroscopy, scanning electron microscopy (SEM), and dynamic light scattering (DLS), and Fourier transform infrared spectrography (FTIR).
Abstract: Currently, nanomaterials with exceptional antibacterial activity have become an emerging domain in research. The optimization of nanomaterials against infection causing agents is the next step in dealing with the present-day problem of antibiotics. In this research work, Ag2O, CoFe2O4, and Ag2O/CoFe2O4/rGO are prepared by chemical methods. Ag2O was prepared by co-precipitation method, while solvothermal technique was utilized for the synthesis of CoFe2O4. The ternary nanocomposite was synthesized by a simple in situ reduction using a two-step approach. The structural and morphological properties were studied by UV-Vis spectroscopy, X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (SEM), dynamic light scattering (DLS), and Fourier-transform infrared spectroscopy (FTIR). From the X-ray diffraction analysis, the crystallite size is found to be 14 nm, 5 nm, and 6 nm for Ag2O, CoFe2O4, and Ag2O/CoFe2O4/rGO respectively. The synthesized nanomaterials were investigated for antibacterial activities against gram-positive strain Staphylococcus aureus (S. aureus) and gram-negative strain Escherichia coli (E. coli) using Agar well diffusion method. Ag2O and CoFe2O4 showed zones of inhibition (ZOI) of 13 mm and 11 mm against gram positive bacteria while 12 mm against gram negative bacteria respectively, while ternary nanocomposite showed 14 mm and 13 mm of ZOI. The antibacterial activity of nanomaterials showed a gradual increment with an increase in the concentration of the materials. Ag2O, CoFe2O4, and Ag2O/CoFe2O4/rGO showed minimum inhibitory concentration (MIC) values of 4.5, 6.5, and 4.5 μg/mL for S. aureus and 6.5, 7.2, and 4.8 μg/mL for E. coli respectively. Minimum bactericidal concentrations were found to be same as the MIC values. Additionally, a time-kill curve analysis was performed and for ternary nanocomposite; the killing response was most effective as the complete killing was achieved at 3 h of incubation at 3-MIC (9.75 μg/mL). These results demonstrate that all the nanomaterials, as a kind of antibacterial material, have a great potential for a wide range of biomedical applications.
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TL;DR: In this article, the authors focus on the properties of quantum dots and their ability to join the dots into complex assemblies creates many opportunities for scientific discovery, such as the ability of joining the dots to complex assemblies.
Abstract: Current research into semiconductor clusters is focused on the properties of quantum dots-fragments of semiconductor consisting of hundreds to many thousands of atoms-with the bulk bonding geometry and with surface states eliminated by enclosure in a material that has a larger band gap. Quantum dots exhibit strongly size-dependent optical and electrical properties. The ability to join the dots into complex assemblies creates many opportunities for scientific discovery.
10,737 citations
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01 Jun 1972
TL;DR: In this paper, the authors present materials at the practical rather than theoretical level, allowing for a physical, quantitative, measurement-based understanding of magnetism among readers, be they professional engineers or graduate-level students.
Abstract: Introduction to Magnetic Materials, 2nd Edition covers the basics of magnetic quantities, magnetic devices, and materials used in practice. While retaining much of the original, this revision now covers SQUID and alternating gradient magnetometers, magnetic force microscope, Kerr effect, amorphous alloys, rare-earth magnets, SI Units alongside cgs units, and other up-to-date topics. In addition, the authors have added an entirely new chapter on information materials. The text presents materials at the practical rather than theoretical level, allowing for a physical, quantitative, measurement-based understanding of magnetism among readers, be they professional engineers or graduate-level students.
6,573 citations
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TL;DR: In this article, a comprehensive survey of the historical development of the science and technology of ferrite materials as well as applications of the ferrites is presented, with a forecast of the future of ferrites in terms of their chemistry.
Abstract: Ferrites—ceramic ferromagnetic materials—have been considered as highly important electronic materials for more than half a century. During this time, the characteristics of commercial ferrite materials, both soft and hard ferrites, have come to approach theoretical values. The quality of commercial ferrites has been improved through accumulated scientific knowledge and advanced technology. This article provides a comprehensive survey of the historical development of the science and technology of ferrite materials as well as applications of the ferrites. The article also offers a forecast of the future of ferrites in terms of their chemistry.
892 citations
TL;DR: Spectrally selective RF pulses are used to excite and refocus the off‐resonance water surrounding the labeling cells so that only the fluid and tissue immediately adjacent to the labeled cells are visible in the image.
Abstract: Contrast agents incorporating superparamagnetic iron-oxide nanoparticles have shown promise as a means to visualize labeled cells using MRI. Labeled cells cause significant signal dephasing due to the magnetic field inhomogeneity induced in water molecules near the cell. With the resulting signal void as the means for detection, the particles behave as a negative contrast agent, which can suffer from partial-volume effects. In this paper, a new method is described for imaging labeled cells with positive contrast. Spectrally selective RF pulses are used to excite and refocus the off-resonance water surrounding the labeled cells so that only the fluid and tissue immediately adjacent to the labeled cells are visible in the image. Phantom, in vitro, and in vivo experiments show the feasibility of the new method. A significant linear correlation (r = 0.87, P < 0.005) between the estimated number of cells and the signal was observed.
424 citations