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223 results on '"Singh, F."'

30. Synthesis of confined electrically conducting carbon nanowires by heavy ion irradiation of fullerene thin film

Author

Kumar, Amit, Avasthi, D.K., Tripathi, A., Kabiraj, D., Singh, F., and Pivin, J.C.

Subjects
Dielectric films -- Chemical properties, Dielectric films -- Electric properties, Thin films -- Chemical properties, Thin films -- Electric properties, Ion bombardment -- Analysis, Physics
Abstract

The creation of conducting nanowires, parallel to each other in fullerene films by the heavy ion irradiation is described. The results have shown that the irradiation through a nanodimension mask can create a two-dimensional regular pattern of conducting nanochannels with a possibility of variety of applications.

Published
2007

43. Investigation of the precipitation kinetics and changes of magnetic anisotropy of iron particles in ion-irradiated silica gel films by means of electron-spin resonance

Author

Pivin, J.C., Esnouf, S., Singh, F., and Avasthi, D.K.

Subjects
Anisotropy -- Usage, Iron compounds -- Electric properties, Iron compounds -- Magnetic properties, Silica gel -- Electric properties, Silica gel -- Magnetic properties, Dielectric films -- Electric properties, Dielectric films -- Magnetic properties, Thin films -- Electric properties, Thin films -- Magnetic properties, Physics
Abstract

The effect of the density of ion-induced electronic excitations on the nucleation of Fe particles in a silicon-based gel and on the magnetic ordering in SiO2:Fe composites with a volume fraction of metal of a few percent derived from the same gel is examined. Irradiation-induced changes in the magnetic anisotropy of composite films depend on the order of magnitude of electronic energy loss S(sub e).

Published
2005

44. Modifications of ZnO thin films under dense electronic excitation

Author

Kumar, P.M. Ratheesh, Kartha, C. Sudha, Singh, F., Avasthi, D.K., Abe, T., Kashiwaba, Y., Okram, G.S., Kumar M., and Kumar, Sarvesh

Subjects
Dielectric films -- Research, Thin films -- Research, Zinc oxide -- Optical properties, X-rays -- Diffraction, X-rays -- Usage, Physics
Abstract

The spray pyrolyzed ZnO film samples are irradiated using 120 MeV Au ion beam and then characterized using optical absorption and transmission, x-ray diffraction (XRD), electrical resistivity measurements, x-ray photoelectron spectroscopy (XPS), and photoluminescence studies. Details of the effects of irradiation, intensity of peaks of XRD and photoluminescence, electrical restivity of the films, atomic concentration form XPS analysis and variations in carrier concentration are discussed.

Published
2005

45. Structure and photoluminescence studies of ZnS:Mn nanoparticles

Author

Karar, N., Singh, F., and Mehta, B. R.

Subjects
Sulfides -- Electric properties, Zinc compounds -- Electric properties, Photoluminescence -- Analysis, Physics
Abstract

ZnS:Mn is produced in nanocrystalline form by a chemical method using polyvinylpyroledone as a chemical capping agent. The study shows that the prepared pure MnS samples did not show any photoluminescence at room temperature and concludes that the observed photoluminescence is Mn(super 2+) induced in nanocrystalline ZnS host.

Published
2004

46. Investigation of radiation damage using thermal spike model for SHI irradiation on Al2O3.

Author

Patra, Paramita, Shah, Sejal, Toulemonde, M., Sulania, I., and Singh, F.

Subjects
RADIATION damage, NUCLEAR energy, ALUMINUM oxide, ATOMIC force microscopy, IRRADIATION, ION beams
Abstract

The material exposed to energetic radiation may change its properties and performance. Ion beam irradiation is an established method to investigate radiation damage in materials. In the present study, SRIM code is employed as a tool to determine the electronic and nuclear energy losses and displacement per atom (DPA) associated with the damage induced in Al2O3 using 100 MeV Au ion. We have further studied the creation of 100 MeV Au ion induced molten zone along the ion track in Al2O3 in the framework of the thermal spike (TS) model. Using the in-elastic thermal spike model, elastic thermal spike model, and unified thermal spike model, the evolution of lattice temperature and latent track radius as a function of depth of Al2O3 for 100 MeV Au ion irradiation are investigated. The current results demonstrate that the latent track radius shows a U-shaped variation based on the combined effect of electronic stopping power and nuclear stopping power. In order to corroborate these results, an additional irradiation experiment was performed using swift heavy ion (SHI), 100 MeV Au ions with fluence 1×1014 ions/cm2 for Al2O3. To investigate the structural properties, surface morphology and to identify the defects in the samples, pristine and irradiated Al2O3 samples were characterized by Grazing Incident X-Ray Diffraction (GIXRD), Atomic Force Microscopy (AFM) and Photoluminescence Spectroscopy (PL). AFM study shows the increase in roughness after SHI irradiation. A decrease in intensity of PL spectra upon SHI irradiation indicates the formation of new defects and disordered structures in the material, which is quite in agreement with the theoretical results. [ABSTRACT FROM AUTHOR]

Published
2022
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