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Significant enhancement of critical current density by effective carbon-doping in MgB2 thin films

  • Ranot, Mahipal (BK21 Physics Division and Department of Physics, Sungkyunkwan University) ;
  • Lee, O.Y. (BK21 Physics Division and Department of Physics, Sungkyunkwan University) ;
  • Kang, W.N. (BK21 Physics Division and Department of Physics, Sungkyunkwan University)
  • Received : 2013.06.04
  • Accepted : 2013.06.27
  • Published : 2013.06.30

Abstract

The pure and carbon (C)-doped $MgB_2$ thin films were fabricated on $Al_2O_3$ (0001) substrates at a temperature of $650^{\circ}C$ by using hot-filament-assisted hybrid physical-chemical vapor deposition technique. The $T_c$ value for pure $MgB_2$ film is 38.5 K, while it is between 30 and 35 K for carbon-doped $MgB_2$ films. Expansion in c-axis lattice parameter was observed with increase in carbon doping concentration which is in contrast to carbon-doped $MgB_2$ single crystals. Significant enhancement in the critical current density was obtained for C-doped $MgB_2$ films as compared to the undoped $MgB_2$ film. This enhancement is most probably due to the incorporation of C into $MgB_2$ and the high density of grain boundaries, both help in the pinning of vortices and result in improved superconducting performance.

Keywords

References

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