We report 75As and 19F NMR studies on the superconducting properties of the newly discovered compound PrFeAsO 0.89F0.11 (Tc=45 K). The Knight shift in the direction of H∥ab-plane decreases below Tc to almost zero, which indicates spin-singlet pairing. The temperature dependencies of both the Knight shift and the spin lattice relaxation rate indicate that there are two gaps opening below Tc, with nodes in the gap function.
ASJC Scopus subject areas
- Physics and Astronomy(all)