Title: Effect of nano-NiO doping on the magnetic susceptibility and flux pinning in MgB₂ superconductor

Authors: Nasser S. Alzayed

Addresses: Department of Physics & Astronomy College of Science, King Saud University P.O. Box 2455, Riyadh, 11451, Saudi Arabia

Abstract: Improving transport properties of polycrystalline MgB₂ by nanoparticle doping has been widely studied by researchers. We have investigated the effect of nano-nickel (as nickel oxide) doping on the critical current density (J_c) of bulk MgB₂ by measuring the ac susceptibility using locally made susceptometer. Samples were doped with nickel at 1%, 2%, 4%, 8% and 10% to investigate for the different quantities on the compound. We have studied the susceptibility as function of the amplitude of ac magnetic field and temperature. The uniformly distributed nano-Ni dopant replaced Mg ions only up to 2% and the rest was distributed uniformly throughout the material and served as pinning centres. J_c for the nano-Ni doped samples has been calculated from susceptibility data and was found to increase as we increased the Ni but saturates after 2%. J_c was enhanced by more than three times with doping. The little change in the XRD peak positions for MgB₂ shown by XRD results indicated that Ni doping did not strongly affect the lattice parameters of MgB₂. Susceptibility measurements reveals that T_c decreased from 37.7 for the pure sample down to 35.6 K for doped samples.

Keywords: MgB2; magnetic susceptibility; susceptometer; superconductors; flux pinning; current density; nano-NiO; Bean|s model; nanoparticles; pinning parameters; magnesium diboride; nanonickel; nickel oxide doping; nanotechnology.

DOI: 10.1504/IJNP.2009.028771

International Journal of Nanoparticles, 2009 Vol.2 No.1/2/3/4/5/6, pp.372-379

Published online: 30 Sep 2009 *

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