Muvattupuzha, India
Muvattupuzha, India

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Javidan A.,Nanoscience Research Center | Ramezani M.,Islamic Azad University of Arak | Sobhani-Nasab A.,Islamic Azad University of Arak | Hosseinpour-Mashkani S.M.,Islamic Azad University of Arak
Journal of Materials Science: Materials in Electronics | Year: 2015

As a new precursor, barium oxalate (BaC2O4) complex was used in a solid-state thermal decomposition process for the synthesis of BaFe2O4 nanoparticles without using any surfactants or additives. The as-synthesized products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectrometry, vibrating sample magneto meter, and EDS. To form pure BaFe2O4, the as-prepared products were calcined at 800 °C for 2 h in a gas mixture of 85 % Ar and 15 % H2. The saturation magnetization, remanent magnetization, and coercivity of the BaFe2O4 nanoparticles were 15, 5 emu/g, and 2500 Oe, respectively. © 2015, Springer Science+Business Media New York.

Aloysius Sabu N.,Nanoscience Research Center | Aloysius Sabu N.,Newman College | Priyanka K.P.,Nanoscience Research Center | Ganesh S.,Mangalore University | And 2 more authors.
Radiation Physics and Chemistry | Year: 2016

In this article we report the post irradiation effects in the structural and optical properties of nanocrystalline calcium tungstate synthesized by chemical precipitation and heat treatment. The samples were subjected to different doses of high-energy electron beam obtained from an 8 MeV Microton. Investigations using X-ray diffraction, scanning electron microscopy and Raman spectra confirmed changes in particle size and structural parameters. However, no phase change was detected for irradiated samples. The stretching/compressive strain caused by high energy electrons is responsible for the slight shift in the XRD peaks of irradiated samples. Modifications in the morphology of different samples were confirmed by scanning electron microscopy. Ultraviolet-visible absorption studies showed variations in the optical band gap (4.08-4.25 eV) upon electron-beam irradiation. New photoluminescence behaviour in electron beam irradiated nanocrystalline CaWO4 was evidenced. A blue shift of the PL peak with increase in intensity was observed in all the irradiated samples. © 2016 Elsevier Ltd.

PubMed | Mangalore University, Nanoscience Research Center and Nehru Arts and Science College
Type: Journal Article | Journal: IET nanobiotechnology | Year: 2016

In this study, the authors investigated antimicrobial activity of TiO2 nanoparticles (NPs) synthesised by sol-gel method. As synthesised TiO2 NPs were characterised by X-ray diffraction, scanning electron microscopy and ultraviolet-visible absorption spectroscopy. The antimicrobial activity of calcined TiO2 nanoparticle samples was examined in day light on Gram positive bacteria (Staphylococcus aureus, Streptococcus pneumonia and Bacillus subtilis), Gram negative bacteria (Proteus vulgaris, Pseudomonas aeruginosa and Escherichia coli) and fungal test pathogen Candida albicans. The synthesised TiO2 NPs were found to be effective in visible light against Streptococcus pneumonia, Staphylococcus aureus, Proteus vulgaris, Pseudomonas aeruginosa and Candida albicans.

Manjunath K.,Jain University | Ravishankar T.N.,Jain University | Kumar D.,BMS College of Engineering | Priyanka K.P.,Nanoscience Research Center | And 7 more authors.
Materials Research Bulletin | Year: 2014

Zinc oxide nanoparticles (ZnO Nps) were successfully synthesized by solution combustion method (SCM) using pigeon pea as a fuel for the first time. X-Ray diffraction pattern reveals that the product belongs to hexagonal system. FTIR spectrum of ZnO Nps shows the band at 420 cm-1 associated with the characteristic vibration of Zn-O. TEM images show that the nanoparticles are found to be ∼40-80 nm. Furthermore, the as-prepared ZnO Nps exhibits good photocatalytic activity for the photodegradation of methylene blue (MB), indicating that they are indeed a promising photocatalytic semiconductor. The antibacterial properties of ZnO nanopowders were investigated by their bactericidal activity against four bacterial strains. © 2014 Elsevier Ltd.

Priyanka K.P.,Nanoscience Research Center | Anu Tresa S.,Mahatma Gandhi University | Jaseentha O.P.,Nanoscience Research Center | Varghese T.,Nanoscience Research Center
Materials Research Express | Year: 2014

Titania nanoparticles were synthesized using the sol-gel method. Nano-sized Ce particles were doped into nanotitania using the metal sol method. As-synthesized TiO2 and Ce doped TiO2 nanoparticles were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible spectroscopy and photoluminescence (PL) spectroscopy. Photocatalytic degradation of methylene blue by undoped and ceria-doped titania was investigated under visible light. The dye degradation capabilities of nano-sized Ce-TiO2 catalysts were found to be superior to undoped TiO2 nanoparticles. The higher photoactivity of TiO2 can be ascribed to the effect of Ce dopants on band gap narrowing, and acting as electron traps on the Ce-TiO2 surface. Dye degradation studies show that nanotitania doped with Ce is suitable for higher photocatalytic activity under visible light. © 2014 IOP Publishing Ltd.

Sreedevi A.,Thejus Engineering College | Priyanka K.P.,Nanoscience Research Center | Babitha K.K.,Nanoscience Research Center | Aloysius Sabu N.,Nanoscience Research Center | And 2 more authors.
Indian Journal of Physics | Year: 2015

Silver tungstate (α-Ag2WO4) nanoparticles were synthesized by chemical precipitation method. Thermodynamic stability of the α-Ag2WO4 nanoparticles was studied by thermogravimetric and differential thermal analysis. These nanoparticles were structurally characterized by X-ray diffraction, Fourier transform infrared spectroscopy and Raman spectroscopy. The structure and morphology of these nanoparticles were studied by scanning electron microscopy and high-resolution transmission electron microscopy. The composition of nanoparticles near and at the surface was estimated by using energy-dispersive X-ray analysis. The optical properties of these nanoparticles were investigated by UV–Visible as well as photoluminescence spectroscopy. The effects of calcination temperature on the geometric parameters and optical properties of α-Ag2WO4 nanoparticle samples was also investigated. © 2015, Indian Association for the Cultivation of Science.

Babitha K.K.,Nanoscience Research Center | Sreedevi A.,Thejus Engineering College | Priyanka K.P.,Nanoscience Research Center | Sabu B.,University of Mumbai | Varghese T.,Nanoscience Research Center
Indian Journal of Pure and Applied Physics | Year: 2015

Cerium oxide (ceria) nanoparticles were synthesized using cerium nitrate and ammonium carbonate as precursors. As-synthesized CeO2 powders were calcined between 400-850°C for 2 h. The samples were characterized by thermogravimetric analysis, X-ray powder diffraction, transmission electron microscopy, Fourier transform infrared, UV-Visible, photoluminescence and Raman spectroscopies. The FTIR spectrum exhibits strong broad band below 600 cm-1 which is due to Ce-O stretching mode to confirm the formation of pure CeO2. It is shown that average particle size increases as calcination temperature is increased and the absorption is red shifted. PL studies observed that emission band is blue shifted and intensity of emission peaks decreases with increase in calcination temperature. Raman spectrum is characterized by the presence of a very strong band near 464 cm-1. The desired structural and optical properties of CeO2 nanoparticles make it as a promising material for photocatalytic and optoelectronic applications.

Priyanka K.P.,Nanoscience Research Center | Babitha K.K.,Vidya Academy of Science and Technology | Sreedevi A.,Thejus Engineering College | Sheena X.,Maharajas College | And 2 more authors.
Journal of Electroceramics | Year: 2014

Cerium oxide nanoparticles were synthesized using cerium nitrate hexa hydrate and ammonium carbonate as precursors. Structural characterizations were done using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The crystallite size and lattice strain on the peak broadening of CeO 2 nanoparticles were studied using Williamson-Hall (W-H) analysis. The dielectric properties of nanocrystalline CeO2 samples with different calcination temperatures, and frequencies have been studied over a temperature range from 303 to 423 K. It is found that the dielectric constant and dielectric loss for all temperatures have high values at low frequencies, which decreases rapidly as frequency is increased and attains a constant value at higher frequencies. The room temperature dielectric constant ε′ obtained for the as prepared CeO2 nanoparticle sample is 61, which constitutes the highest value ever reported at low frequency. A.C. conductivity, which was derived from dielectric constant and loss tangent data, has a low value at smaller frequencies that increases as the frequency is increased. The dielectric constant and a.c. conductivity values are shifted upwards as the temperature is raised. However, these values are decreased as the annealing temperature is increased. The desired structural properties and high dielectric constant of nanophase CeO2 make it as a promising material for the high dielectric constant dielectric gate in complementary metal oxide semiconducting (CMOS) devices. © 2014 Springer Science+Business Media New York.

Javidan A.,Nanoscience Research Center | Rafizadeh S.,Islamic Azad University at Qom | Mostafa Hosseinpour-Mashkani S.,Islamic Azad University at Qom
Materials Science in Semiconductor Processing | Year: 2014

Monoferrite strontium ferrite nanoparticles were successfully synthesized in the presence of strontium oxalate, [(SrC2O4)], as strontium precursor by using solid-state thermal decomposition method. X-ray diffraction study was used to determine phase purity, crystal structure, and average crystallite size of the strontium ferrite nanoparticles. The electrical conductivity measurement of the sintered sample was carried out at 300 °C. Metal nitrates and oxalate precursor without any solvent or surfactant were used in this method; later, they were decomposed at 850 °C for 2 h in a gas mixture of 85% Ar and 15% H2. The average diameter of the strontium ferrite nanoparticles was 40 nm. The as-prepared strontium ferrite nanoparticles were characterized extensively by techniques like XRD, transmission electron microscope (TEM), high-resolution TEM (HRTEM), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), vibrating sample magnetometer (VSM), room temperature photoluminescence (Pl), ultraviolet-visible spectroscopy (UV-vis), and energy dispersive spectrometry (EDS). © 2014 Elsevier Ltd.

George T.,King's College | Sunny A.T.,Kerala University | Varghese T.,Nanoscience Research Center
IOP Conference Series: Materials Science and Engineering | Year: 2015

Cobalt ferrite nanoparticles of average size 18 nm are synthesized by sol-gel method and investigated the magnetic properties. The saturation magnetization value calculated from vibration sample magnetometer (VSM) studies for CoFe2O4 is lower than the reported value for the bulk. The magnetization curves demonstrate a trend towards the superparamagnetic behavior of the as-prepared CoFe2O4 nanoparticles. The microwave magnetic parameters show a decreasing trend with the increase of frequency. © Published under licence by IOP Publishing Ltd.

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