We report on the pairing symmetry and the spin correlations in the Fe(Ni)-based superconductors RFe(Ni)AsO1-xFx (R=Pr, La), LiFeAs and Ba1-xKxFe2As2 single crystals, based on our extensive nuclear magnetic resonance and nuclear quadrupole resonance measurements. The spin susceptibility measured by the Knight shift decreases below Tc along all crystal directions, which indicates spin-singlet pairing. Evidence for multiple gaps is given. We find that the antiferromagnetic spin fluctuation is anisotropic in the spin space due to spin-orbit coupling, but becomes isotropic in the zero temperature limit, which points to spin-singlet superconductivity with nodeless gap.
|Journal||Journal of Physics: Conference Series|
|Issue number||PART 2|
|Publication status||Published - 2012|
|Event||26th International Conference on Low Temperature Physics, LT 2011 - Beijing, China|
Duration: Aug 10 2011 → Aug 17 2011
ASJC Scopus subject areas
- Physics and Astronomy(all)