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TT: Fachverband Tiefe Temperaturen
TT 5: Postersession Superconductivity: Materials - Fabrication and Properties
TT 5.36: Poster
Montag, 23. März 2009, 13:00–16:45, P1A
NMR studies on the new iron arsenide superconductors including the superconducting state — •Hans-Joachim Grafe1, Guillaume Lang1, Franziska Hammerath1, Dalibor Paar1,2, Katarina Manthey1, Nicholas Curro3, Günther Behr1, Jochen Werner1, and Bernd Büchner1 — 1IFW Dresden, Helmholtzstr. 20, D-01069 Dresden, Germany — 2Dept. of Physics, Faculty of Science, Univ. of Zagreb, P. O. Box 331, — 3Dept. of Physics, Univ. of California, Davis, CA 95616, USA
We summarize our Nuclear Magnetic Resonance (NMR) and Nuclear Quadrupole Resonance (NQR) results on the new iron arsenide superconductor LaO1−xFxFeAs in the normal state [1,2], and show new NMR data in the superconducting state. Beyond early evidence of nodes and spin-singlet pairing [2], we find evidence of a deviation of the T3 behaviour of the spin lattice relaxation rate, 1/T1, at temperatures significantly below Tc, which would agree with the suggested extended s-wave symmetry [3]. The deviation of the T3 behaviour is induced by the pair breaking effect of impurities. Different amounts of impurities would lead to different temperature dependences of 1/T1, which would allow to differentiate between d-wave and extended s-wave symmetries.
[1] H.-J. Grafe et al., arXiv:0811.4508
[2] H.-J. Grafe et al., PRL 101, 047003 (2008)
[3] A. Chubukov et al., PRB 78, 134512 (2008)