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Journal Articles Vacuum Year : 2010

Magnetic and field emission studies of atom beam sputtered Ni:SiO(2) granular films

H. Kumar
  • Function : Author
S. Ghosh
  • Function : Author
D. K. Avasthi
  • Function : Author
D. Kabiraj
  • Function : Author
N. P. Lalla
  • Function : Author
T. Shripathi
  • Function : Author

Abstract

Ni:SiO(2) granular films have been prepared by atom beam sputtering technique under ambient conditions. These films have been subsequently annealed at 200-600 degrees C temperature. GAXRD and TEM analyses show the growth of Ni particles and improvement in crystallinity with increase in annealing temperature. Selected area electron diffraction and XPS analyses show the presence of a small quantity of NiO phase in addition to metallic Ni. Room temperature magnetic measurements indicate that the films annealed at lower temperatures (<= 400 degrees C) are superparamagnetic and the film annealed at 600 degrees C is ferromagnetic. Magnetic results at 5 K are explained on the basis of exchange bias between Ni particles and surrounding nickel oxide. Systematic field emission studies on as-deposited and annealed films show a turn-on field similar to 6.2-13.5 V/mu m corresponding to an emission current density of similar to 1 A/m(2). Field emission results are explained on the basis of electrical inhomogeneity effects. (C) 2010 Elsevier Ltd. All rights reserved.

Dates and versions

in2p3-00667228 , version 1 (07-02-2012)

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H. Kumar, S. Ghosh, D. K. Avasthi, D. Kabiraj, N. P. Lalla, et al.. Magnetic and field emission studies of atom beam sputtered Ni:SiO(2) granular films. Vacuum, 2010, 85, pp.139-144. ⟨10.1016/j.vacuum.2010.04.017⟩. ⟨in2p3-00667228⟩
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