59Co and 75As NMR Investigation of Electron-Doped High Tc Superconductor BaFe1.8Co0.2As2 (Tc = 22 K) Academic Article uri icon

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  • We report an NMR investigation of the superconductivity in BaFe(2)As(2) induced by Co doping (Tc=22K). We demonstrate that Co atoms form an alloy with Fe atoms and donate carriers without creating localized moments. Our finding strongly suggests that the underlying physics of iron-pnictide superconductors is quite different from the widely accepted physical picture of high Tc cuprates as doped Mott insulators. We also show a crossover of electronic properties into a low temperature pseudo-gap phase with a pseudo-gap Delta 560K, where chi(spin) constant and resisitivty T. The NMR Knight shift below Tc decreases for both along the c-axis and ab-plane, and is consistent with the singlet pairing scenario.


  • Ning, Fanlong
  • Ahilan, Kanagasingham
  • Imai, Takashi
  • S. Sefat, Athena
  • Jin, Ronying
  • A. McGuire, Michael
  • C. Sales, Brian
  • Mandrus, David

publication date

  • October 15, 2008