title: 75As NMR studies of superconducting LaFeAsO0.9F0.1.
abstract: We have performed 75As nuclear magnetic resonance measurements on aligned powders of the new LaFeAsO0.9F0.1 superconductor. In the normal state, we find a strong temperature dependence of the spin shift and Korringa behavior of the spin lattice relaxation rate. In the superconducting state, we find evidence for line nodes in the superconducting gap and spin-singlet pairing. Our measurements reveal a strong anisotropy of the spin lattice relaxation rate, which suggests that superconducting vortices contribute to the relaxation rate when the field is parallel to the c axis but not for the perpendicular direction.
authors.affiliation: IFW Dresden, Institute for Solid State Research, P.O. Box 270116, D-01171 Dresden, Germany.
authors.forename: H-J
authors.initials: HJ
authors.lastname: Grafe
authors.forename: D
authors.initials: D
authors.lastname: Paar
authors.forename: G
authors.initials: G
authors.lastname: Lang
authors.forename: N J
authors.initials: NJ
authors.lastname: Curro
authors.forename: G
authors.initials: G
authors.lastname: Behr
authors.forename: J
authors.initials: J
authors.lastname: Werner
authors.forename: J
authors.initials: J
authors.lastname: Hamann-Borrero
authors.forename: C
authors.initials: C
authors.lastname: Hess
authors.forename: N
authors.initials: N
authors.lastname: Leps
authors.forename: R
authors.initials: R
authors.lastname: Klingeler
authors.forename: B
authors.initials: B
authors.lastname: Büchner