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  • Author: Shridhar N. Mathad x
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Synthesis and structural analysis of Ni0.45Cu0.55Mn2O4 by Williamson–Hall and size–strain plot methods

Abstract

This paper describes synthesis and structural properties of Ni0.45Cu0.55Mn2O4 nanopowder, obtained by co-precipitation route. XRD pattern reveals cubic structure with lattice parameter 8.305 Å. We report crystallite size (D), micro strain (ε), dislocation density (ρD), and hopping lengths (LA and LB). We also report preferential orientation by texture coefficients [Tc (h k l)]. The Williamson-Hall plot and stress-strain plot also employed to understand the mechanical properties of materials.

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Morphological and FTIR Studies of Barium Oxalate Single Crystals

Abstract

The conditions for the gel growth of barium oxalate single crystals in silica gels were studied in this paper. We describe the growth mechanism, effect concentration of feed solution, interchanging of the reactants, the effect of temperature and detailed study of microstructures of barium oxalate single crystals. At higher concentration of feed solution dense fibers were observed. With interchanged feed solution precipitate and spherulites have been obtained. The effect of temperature on growth barium oxalate crystals showed that there was a decrease in nucleation density at higher temperature. The crystals growth were observed under the electron microscope which revealed that the crystal have needle and spherulites structures. We also report the FTIR studies of barium oxalate crystals.

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The evaluation of kinetic parameters for cadmium doped Co-Zn ferrite using thermogravimetric analysis

Abstract

This work had the objective to analyze the thermodynamic properties of cadmium doped cobalt zinc ferrite (Co0.5Zn0.5Cd0.3Fe1.8O4), obtained by solid state reaction method and characterized by TGA-DTA. The TG analysis show sharp peaks at four points, two for water reduction, one for decomposition of chlorides and last one for formation of end product. The ratio of weight of end product to starting material match with ratio of molecular weight of end product and starting materials; this confirms the formation of ferrite sample. Broido, Coats-Redfern, Chang and Horowitz-Metzger approximations are employed to compute the activation energy (E a) of formation of ferrite sample. The kinetic parameters like frequency factor (A), entropy change (ΔS), enthalpy change (ΔH) and changes in internal energy (ΔG) of sample are also reported.

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Magnetic and Antibacterial Studies of Nanoferrites Prepared by Self Propagating High-Temperature Synthesis Route

Abstract

The main objective of the manuscript is the structural analysis, magnetic investigation and antimicrobial activity of Mn1−xZnxFe2O4 with stoichiometry (x = 0, 0.25, 0.5, 0.75, and 1.0). The Mn-Zn nanoferrites were synthesized by self propagating high-temperature synthesis using a mixture of fuels. The synthesized Mn-Zn nanoferrites were characterized by X-ray diffraction (XRD) that confirms cubic crystal structure with lattice constant in the range 8.372-8.432Ao. It is observed that saturation magnetization (Ms), remanence magnetization (Mr) and magneton number (Mr/Ms) decreased gradually with the increasing of Zn2+ concentration. The decrease in the saturation magnetization may be explained as, the Zn2+ concentration increases, the relative number of ferric ions on the A sites diminishes and this reduces the A–B interaction. Further, the synthesized Mn-Zn nanoferrites were tested for antibacterial activities against two-gram positive strains (Staphylococcus aureus ATCC No–12598, Lactobacillus amylovorus ATCC No– 12598), gram-negative strains E.coli ATCC No – 25922, Pseudomonas- ATCC No- 25619) and one fungal strain (C.albicans -ATCC No – 2091).

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Synthesis, Structural and Electrical Studies of Li-Ni-Cu Nano Ferrites

Abstract

Li-Ni ferrite has gained great scientific elicit owing to of its unparalleled properties and applications. The copper doped Li-Ni ferrite has been synthesized by sucrose method. The structure was characterized by X-ray diffraction, which has confirmed the formation of single-phase spinel structure. X-ray diffraction and FTIR data reveals the formation of cubic structure phase. Unit cell parameters vary with copper content; overall variation of the unit cell parameters obeys Vegard’s law. The main absorption bands of spinel ferrite have appeared through IR absorption spectra recorded in the range of 300–700 cm−1. The copper concentration dependence of lattice parameters obeys Vegard’s law. DC electrical resistivity of the prepared samples decreases with increasing in the temperature which shows the semiconducting behaviour of all nano ferrites. The most prominent influence copper doping on the electrical properties of Li-Ni ferrites has been reported.

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