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Dixit G.,Inter University Accelerator Center | Dixit G.,Gb Pant University Of Ag And Technology | Singh J.P.,Inter University Accelerator Center | Chen C.L.,Academia Sinica, Taiwan | And 5 more authors.
Journal of Alloys and Compounds | Year: 2013

Present work reports the structural, morphological, electrical properties of the Ce doped nickel ferrite (NiFe2O4) compounds and their electronic structures studied by X-ray absorption spectroscopy. The samples of NiFe2-xCexO4 (x = 0.0-0.10) were prepared by the chemical route and sintered at 1100 °C for 3 h. X-ray diffraction patterns of these sintered pellets show that Ce doped samples exhibit pure spinel phase up to x = 0.03. With increase of Ce concentration the crystallite size of the samples change randomly, however lattice parameters do not exhibit any significant change. Temperature dependent resistivity shows semiconducting nature for all the compositions. Sample with Ce concentration x = 0.04 shows maximum resistivity. The sample with x = 0.02 shows highest dielectric constant in the frequency range of 75 kHz-1 MHz at room temperature. The observed results are discussed on the basis of change in the electronic structure of these compounds with the Ce concentration. It has been observed that valence state of Ce ion is playing dominant role in determining the electrical and dielectric properties of the synthesized system. © 2013 Elsevier B.V. All rights reserved.


Singh J.P.,Gb Pant University Of Ag And Technology | Srivastava R.C.,Gb Pant University Of Ag And Technology | Agrawal H.M.,Gb Pant University Of Ag And Technology | Chand P.,Indian Institute of Technology Kanpur | Kumar R.,Indian National Institute of Engineering
Current Applied Physics | Year: 2011

The present investigation aims to study the swift heavy ion irradiation induced effects in zinc ferrite nanoparticles through X-ray diffractometry, transmission electron microscopy and electron paramagnetic resonance spectroscopy. A series of zinc ferrite nanoparticles having different crystallite sizes ranging from 12 to 62 nm have been synthesized by using the nitrates of cations and the citric acid as the host. These samples were irradiated by 100 MeV oxygen beam with two fluences 1 × 1013 and 5 × 1013 ions/cm2. The XRD patterns show the deterioration of crystalline phase after irradiation. The average crystallite size decreases after irradiation. EPR analyses of the pristine and irradiated samples show that the changes depend on the average crystallite size of the pristine samples. Further, the pristine sample having a crystallite size of 62 nm passes through dominant changes after irradiation. It was observed that the number of magnetic centres decreases in the irradiated samples. © 2010 Elsevier B.V. All rights reserved.


Pandey B.,Gb Pant University Of Ag And Technology | Pandey K.,Ajay Kumar Garg Engineering College | Agrawal H.M.,Gb Pant University Of Ag And Technology
Annals of Nuclear Energy | Year: 2011

The excitation functions of (n,p) reactions for the stable isotopes of Cr, Fe and Ni were calculated using EMPIRE 3.0 β1 (ARCOLE) from threshold to 20 MeV. The cross-sections are calculated using full featured Hauser-Feshbach statistical model with pre-equilibrium effects by invoking DEGAS option in the code. A good agreement between the calculated and experimental data (EXFOR data base) as well as evaluated data is obtained with option of neutron and proton potentials by Koning (Global) and HFB parity dependent nuclear level density. This is an important step to the validation of nuclear model with superior predictive power. The compound nucleus and pre-equilibrium reaction mechanisms as well as the isotopic effects were also studied. © 2010 Elsevier Ltd. All rights reserved.


Kumar P.,Indian Institute of Technology Delhi | Kumar P.,Inter University Accelerator Center | Singh V.,National Institute of Technology Kurukshetra | Sharma V.,Malaviya National Institute of Technology, Jaipur | And 3 more authors.
Ceramics International | Year: 2015

We report the effect of phase segregation on the structural, morphological, and optical properties of sol-gel synthesized Zn1-xYxO samples in dilute concentration of 1-5 %. X-ray diffraction patterns confirm that below 3% of Y doping, pure ZnO wurtzite structure phase is obtained and phase segregation of Y2O3 appears at x-0.03. XRD results are well supported by the results obtained from scanning electron microscopy, Photoluminescence and Raman spectroscopy techniques. The difference in the charge states, ionic radii and the coordination numbers of host lattice and dopant ions leads to the phase segregation. © 2015 Elsevier Ltd and Techna Group S.r.l.


Singh J.P.,Gb Pant University Of Ag And Technology | Srivastava R.C.,Gb Pant University Of Ag And Technology | Agrawal H.M.,Gb Pant University Of Ag And Technology | Kumar R.,Indian National Institute of Engineering
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms | Year: 2010

Present investigation reports the effect of 100 MeV oxygen beam on the magnetic properties of zinc ferrite nanoparticles. The nanoparticles for this study were synthesized by using the nitrates of zinc and iron in the matrix of citric acid and by sintering the precursor at 500 and 1000 °C. Both these samples were irradiated by 100 MeV oxygen beam with two different fluence 1 × 1013 and 5 × 1013 ions/cm2. Besides the presence of cubic spinel phase, ZnO phase appears after the irradiation in both the samples. A decrease in average particle size was observed in the irradiated samples as estimated by X-ray diffraction pattern. The magnetization versus applied field curves show the decrease in magnetization with the fluence of the beam, which is attributed to the ZnO phase. The thermal magnetization curve for the sample ZF500 shows almost constant value of blocking temperature after irradiation whereas for ZF1000 it increases from 18 K to 32 K at a fluence of 5 × 1013 ions/cm2. © 2010 Elsevier B.V. All rights reserved.


Massey S.,Gb Pant University Of Ag And Technology | Maurya R.,Gb Pant University Of Ag And Technology
Man-Made Textiles in India | Year: 2012

Saree has always been the favourite garment of women in India. It has a timeless charm and is the most favoured garment worn at formal occasions and at religious ceremonies. Varanasi has long been famous for its brocades and sarees. The demand of Varanasi saree in National and International market promoted the weaving of sarees on a vast scale. Hence, in the present study an attempt has been made to study the technical details of Varanasi sarees i.e. designs, motifs, dyes and embellishments. 120 respondents were selected from different weaving units of Varanasi city through proportional technique. The data collected by interview schedule was tabulated and analyzed using frequency, percentage and weighted scores.


Singh J.P.,Inter University Accelerator Center | Dixit G.,Gb Pant University Of Ag And Technology | Srivastava R.C.,Gb Pant University Of Ag And Technology | Agrawal H.M.,Gb Pant University Of Ag And Technology | Asokan K.,Inter University Accelerator Center
Journal of Physics D: Applied Physics | Year: 2011

This paper reports the study of structural, electrical, magnetic and optical properties of Gd-doped nickel ferrite nanoparticles in order to investigate the possibility of multiferroism. The NiGd0.04Fe 1.96O4 nanoparticles were prepared by a chemical route and characterized by various techniques. Doping with Gd ions induces poor ferroelectricity in nickel ferrite. This may be attributed to the small distortion in the centrosymmetric fcc structure because of the presence of large Gd ions. © 2011 IOP Publishing Ltd.


Kapri A.,Gb Pant University Of Ag And Technology | Zaidi M.G.H.,Gb Pant University Of Ag And Technology | Satlewal A.,Gb Pant University Of Ag And Technology | Goel R.,Gb Pant University Of Ag And Technology
International Biodeterioration and Biodegradation | Year: 2010

Superparamagnetic iron oxide nanoparticles (SPION) with size ranging 10.6-37.8 nm were synthesized and characterized through XRD, FT-IR spectra, simultaneous TG-DTG-DTA, vibrational sample magnetometry (VSM) and transmission electron microscopy (TEM). Effect of SPION size variants on the growth-profile of Low-Density Polyethylene (LDPE) degrading microbial consortium consisting of Microbacterium sp., Pseudomonas putida and Bacterium Te68R was monitored in Minimal broth Davis medium lacking iron and dextrose. Besides accelerating the bacterial growth, these nanoparticles also improved the exponential phase durability by 36 h. Further, shifting in lag-phase and the additive effect of sonication was also documented on growth profiling. SPION of size 10.6 nm were selected and were found to significantly increase the biodegradation efficiency of consortium as revealed by λ-max shifts, Fourier transform infrared spectroscopy (FT-IR) and simultaneous thermogravimetric-differential thermogravimetry-differential thermal analysis (TG-DTG-DTA). The study highlights the significance of bacteria-nanoparticle interactions which can dramatically influence key metabolic processes like biodegradation. © 2010 Elsevier Ltd. All rights reserved.


Rana G.,Gb Pant University Of Ag And Technology | Kandpal D.,Gb Pant University Of Ag And Technology | Johri U.C.,Gb Pant University Of Ag And Technology
AIP Conference Proceedings | Year: 2013

Magnetite nanoparticles are synthesized using Co-precipitation method at two different initial pH values (12 and 10). The phase confirmation is obtained using X-ray diffraction. The crystallite size for the samples is found to be 16 nm and 9 nm respectively. The cation distribution for both samples differs from their bulk counterparts. The dielectric constant for the sample of crystallite size 9 nm is higher which is attributed to the cation distribution. © 2013 American Institute of Physics.


Negi P.,Gb Pant University Of Ag And Technology | Agrawal H.M.,Gb Pant University Of Ag And Technology | Srivastava R.C.,Gb Pant University Of Ag And Technology
International Journal of Materials Engineering Innovation | Year: 2014

Here, we report the structural, specific heat and magnetoresistive properties of orthorhombic perovskite structured Gd0.7Ca0.3MnO3, synthesised by modified sol-gel technique. X-ray diffraction along with the Rietveld refinement confirms the pure phase of the sample and the crystallite size comes out to be ̃42 nm. Scanning electron micrograph shows the grain distribution having average particle size ̃71 nm. Energy dispersive spectroscopy confirms the stoichiometry of the composition. The sample is also characterised by Raman spectroscopy for structural and phase confirmation. The functional group of Gd0.7Ca0.3MnO3 was also analysed from its Fourier transform infrared (FTIR) spectrum. The specific heat of the sample is measured in the temperature range of 2 to 300 K. Resistivity measurements with and without magnetic field was performed. The activation energy in absence of magnetic field is 0.162 eV which reduces to 0.154 eV in presence of 8 T magnetic field. The observed electrical behaviour is explained in terms of polaron hopping mechanism. Copyright © 2014 Inderscience Enterprises Ltd.

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