19-F NMR Investigation of Iron-pnictide Superconductor   LaFeAsO(0.89)F(0.11)
  We report 19-F NMR investigation of the new high temperature superconductor LaFeAsO(0.89)F(0.11) (Tc ~ 28K). We demonstrate that low frequency spin fluctuations exhibit pseudo gap behavior above Tc. We also deduce the London penetration depth lambda from NMR line broadening below Tc. 
K. Ahilan, F. L. Ning, T. Imai, A. S. Sefat, R. Jin, M.A. McGuire,   B.C. Sales, D. Mandrus