Kuldeep Chand Verma; R.K. Kotnala
Abstract
We reported the Core/Shell structures of CoFe2-xCexO4 (CFCeO) nanoparticles were prepared by a chemical combustion method. The Rietveld refinement of X-ray diffraction pattern results into CoFe2O4 spinel structure and thevariation in lattice parameters have been found with doping of Ce ions. Transmission ...
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We reported the Core/Shell structures of CoFe2-xCexO4 (CFCeO) nanoparticles were prepared by a chemical combustion method. The Rietveld refinement of X-ray diffraction pattern results into CoFe2O4 spinel structure and thevariation in lattice parameters have been found with doping of Ce ions. Transmission Electron Microscopy analysis has shown Core/Shell type nanoparticles. The stoichiometric composition of Co, Fe, Ce and O atoms has been analyzed through X-ray fluorescence elemental detection. Fourier transform infrared spectra could detect organic extent, tetrahedral (Fe-O), octahedral (Fe(Ce)-O-Co) and lattice disorder in CFO nanoparticles with Ce doping. Defects related oxygen vacancies are analyzed in Photoluminescence emission spectra. The room temperature magnetic measurement of CFO nanoparticles is highly influenced with Ce ions. The magnetic interactions are antiferromagnetic at room temperature that confirmed by zero field cooling and field cooling magnetic measurements at 100 Oe. However, the spin glass and ferromagnetic clustered growth may also exist in CFCeO samples that reduce room temperature ferromagnetism. The dielectric measurement indicates polarization up to higher frequency region that enhanced with Ce ions.
Abhishek Shukla; S.C. Singh; B.K. Pandey; K.N. Uttam; J. Shah; R.K. Kotnala; R. Gopal
Abstract
Titanium ferrite nanoparticles (NPs) with controlled titanium to iron ratios (Ti/Fe) were synthesized using liquid-assisted pulsed laser ablation (LA-PLA) technique. Present manuscript describes effect of variation of Ti/Fe ratio in the target and the effect of laser pulse energy on size, shape, optical ...
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Titanium ferrite nanoparticles (NPs) with controlled titanium to iron ratios (Ti/Fe) were synthesized using liquid-assisted pulsed laser ablation (LA-PLA) technique. Present manuscript describes effect of variation of Ti/Fe ratio in the target and the effect of laser pulse energy on size, shape, optical band gap, crystalline phase and magnetic properties of as-synthesized titanium ferrite NPs. UV-visible absorption, TEM and XRD investigations reveal that size of as-produced NPs decreases with the increase of Ti in the Ti/Fe targets used for ablation. Variation in laser pulse energy at a given Ti/Fe ratio has lesser dependence on size, shape and magnetic properties of produced NPs. Higher ferromagnetism with larger sized particles demonstrates dominance of bulk phenomenon over surface defects for the generation of ferromagnetic responsible spins. As-produced titanium ferrite nanomaterials may be used as promising magnetic recovery catalysts (MRCs).
Gagan Kumar; Virender Pratap Singh; Arun Kumar; Jyoti Shah; Shalendra Kumar; B.S. Chauhan; R.K. Kotnala; M. Singh
Abstract
We investigated the effects of In 3+ and Co 2+ substitutions on the structural and magnetic properties of Mg-Mn ferrites. The cation distribution technique was taken into account to estimate the magnetic interactions. Cation distribution was also used to investigate the ionic radii of tetrahedral and ...
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We investigated the effects of In 3+ and Co 2+ substitutions on the structural and magnetic properties of Mg-Mn ferrites. The cation distribution technique was taken into account to estimate the magnetic interactions. Cation distribution was also used to investigate the ionic radii of tetrahedral and octahedral sites, oxygen positional parameter, site bond as well as edge lengths, bond lengths and bond angles. The ionic radius of tetrahedral site and octahedral site was observed to increase with the incorporation of In 3+ and Co 2+ ions respectively. Theoretical lattice parameter was observed to increase with the substitution of In 3+ and Co 2+ ions. In 3+ substitution resulted in weakening of super-exchange interactions while in Co 2+ substituted Mg-Mn ferrites, anisotropy was observed to play a decisive role in addition to bond lengths and bond angles.
Jaspreet Kaur; Jasneet Kaur; Jyoti Shah; R.K. Kotnala; Vinay Gupta; Kuldeep Chand Verma
Abstract
In the present work, structural, microstructural and magnetoelectric (ME) coupling of multiferroic Ba(Fe0.01Ti0.99)O3 (BFT1) nanowires have been studied. BFT1 nanowires were prepared by a hydrothermal method with reaction temperature 180 o C for 48 hours. The X-ray diffraction shows that BFT1 is polycrystalline ...
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In the present work, structural, microstructural and magnetoelectric (ME) coupling of multiferroic Ba(Fe0.01Ti0.99)O3 (BFT1) nanowires have been studied. BFT1 nanowires were prepared by a hydrothermal method with reaction temperature 180 o C for 48 hours. The X-ray diffraction shows that BFT1 is polycrystalline with cubic phase. The calculated value of distortion ratio (c/a) is ~ 1. No impurity or extra phase is observed. The micrographs by transmission electron microscopy reveal nanowires like structure of BFT1with diameter lie in the range of ~ 40 - 50 nm and length greater than 1.5 μm. The ME coefficient measurement shows that the ME coupling under the effect of both ac and dc bias. It shows strong dependence on ac and dc bias applied field. The value of linear coefficient (α) called ME coefficient is calculated as ~ 16 mV/Oecm at a fixed frequency of 850 Hz. This ME coefficient α corresponds to induction of polarization by a magnetic field or of magnetization by an electric field. The observed optimum dc bias field at which the maximum magneto-electric coupling occurs is ~ 750 Oe. The magnetization hysteresis shows strong ferromagnetism.
