Nanomaterials & Nanotechnology
Praveena G; Mohammed E.M.; Viji C.; Shyam Kumar S.
Abstract
Nickel ferrite (NiFe₂O₄) nanoparticles were synthesized using the sol-gel auto combustion method, and the powdered samples were calcined at two temperatures, 100°C and 200°C. The structure of nickel ferrite nanoparticles was determined using X-ray diffraction (XRD) patterns. The nickel ferrite ...
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Nickel ferrite (NiFe₂O₄) nanoparticles were synthesized using the sol-gel auto combustion method, and the powdered samples were calcined at two temperatures, 100°C and 200°C. The structure of nickel ferrite nanoparticles was determined using X-ray diffraction (XRD) patterns. The nickel ferrite nanoparticle size was calculated using the Debye-Scherrer formula and was found to be 15.53 nm and 17.14 nm for 100 °Cand 200 °C. Field Emission Scanning Electron Microscopic (FESEM) analysis reveals that the samples exhibit spherical morphology with crystalline in nature and also show some agglomeration. The phase formation of nickel ferrite nanoparticles was further confirmed from the energy dispersive x-ray (EDAX) spectra which shows strong peaks for the existence of all the elements in it. The work investigates the magnetic properties of the samples and both the samples exhibit ferromagnetic behavior. The optical band gap obtained for the samples is 2.5 and 2.6 eV for N1 and N2 samples. The antimicrobial activity especially the anti-algal effect of NiFe₂O₄ nanoparticles on freshwater microalgae Chlorella pyrenoidosa in a dose-dependent manner is also reported.
Subhash B. Kondawar; Arti I. Nandapure; Bharti I. Nandapure
Abstract
Nanocrystalline nickel ferrite (NiFe2O4) powder of crystallite size ~20 nm was synthesized by refluxing method. Electrically conductive polyaniline-nickel ferrite (PANI/NiFe2O4) nanocomposites have been synthesized by an in-situ polymerization of aniline monomer in the presence of as-prepared NiFe2O4 ...
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Nanocrystalline nickel ferrite (NiFe2O4) powder of crystallite size ~20 nm was synthesized by refluxing method. Electrically conductive polyaniline-nickel ferrite (PANI/NiFe2O4) nanocomposites have been synthesized by an in-situ polymerization of aniline monomer in the presence of as-prepared NiFe2O4 in different weight percentage (5%, 10%, and 15%). These nanocomposites were subsequently characterized for morphological, crystalline, structural, electrical and magnetic properties by Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), Four Probe Resistivity (FPR) and Vibrating Sample Magnetometer (VSM). Existence of NiFe2O4 in the nanocomposites was confirmed by XRD, FTIR and TEM analysis. The change in morphology with crystallite size ? 50 nm was observed for the nanocomposites clearly indicate the coating of PANI on NiFe2O4 . Nanocomposites showed increase in saturation magnetization as compared to that of PANI and increase in electrical conductivity as compared to that of NiFe2O4 indicating the synergistic effect of individual components. The saturation magnetization drastically increased as nickel ferrite content changed from 5 to 15% in nanocomposites. The conductivity of nanocomposites increased with temperature, exhibiting typical semiconductor behavior. The nanocomposites show semiconducting and ferromagnetic behaviour. The electrical conductivity of nanocomposites decreased from 1.089 to 0.268 S/cm, but saturation magnetization increased from 0.97 to 2.803 emu/g, when ferrite content changed from 5 to 15 wt%, indicates such nanocomposites are good for electromagnetic devices.
Gagan Dixit; J.P. Singh; R.C. Srivastava; H.M. Agrawal; R.J. Chaudhary
Abstract
In the present work, structural, morphological, magnetic and optical properties of nickel ferrite thin films having different thickness are reported. All the films were deposited on Si (100) substrate by pulsed laser deposition technique. Thicknesses of the films determined by x-ray reflectivity vary ...
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In the present work, structural, morphological, magnetic and optical properties of nickel ferrite thin films having different thickness are reported. All the films were deposited on Si (100) substrate by pulsed laser deposition technique. Thicknesses of the films determined by x-ray reflectivity vary from 62 to 176nm as the deposition time varies from 16 min to 40 min. The films were characterised by x-ray diffractogram, Fourier transform infrared (FTIR) and Raman spectroscopy for structural and phase confirmation. FTIR and Raman spectra confirm mixed spinel nature of nickel ferrite. Surface morphology is studied by Atomic force microscopy. All the films have granular nature. Magnetic properties were studied by vibrating sample magnetometer and magnetic hysteresis curves were recorded for all the films at room temperature and at10K. At 10K, saturation magnetisation was found to increase while coercivity deceases with thickness. The results are explained on the basis of anisotropy induced by cation inversion and strain. Optical properties were studied by UV-vis reflectance spectra. The value of optical band gap (5.7eV) was found to be independent of thickness of the film.
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