Systematic A 75 s NMR study of the dependence of low-lying excitations on F doping in the iron oxypnictide LaFeAsO1-x Fx

Yusuke Nakai, Shunsaku Kitagawa, Kenji Ishida, Yoichi Kamihara, Masahiro Hirano, Hideo Hosono

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We report A 75 s NMR studies on LaFeAs (O1-x Fx) (0≤x≤0.14). At x=0.04 near the phase boundary, from resistivity, spin-lattice relaxation rate 1/ T1, and NMR spectrum measurements, we found weak magnetic order at TN □30 K. Antiferromagnetic (AFM) fluctuations proved through 1/ T1 are suppressed significantly with F doping, and pseudogap behavior without pronounced AFM fluctuations is observed at x=0.11 where TC is maximum. This significant suppression of 1/ T1 T upon F doping while TC remains nearly unchanged suggests that low-energy AFM fluctuations probed with A 75 s NMR do not play a crucial role in the superconductivity.

Original languageEnglish
Article number212506
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number21
Publication statusPublished - 2009 Jun 11


ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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