Dresden 2014 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 30: Superconductivity - Poster Session
TT 30.31: Poster
Monday, March 31, 2014, 15:00–19:00, P2
High-field NMR spectroscopy of the iron-based superconductor LiFeAs — •Hannes Kühne1,2, Arneil P. Reyes2, Philip L. Kuhns2, Hans-Joachim Grafe3, Saicharan Aswartham3, Sabine Wurmehl3, and Bernd Büchner3 — 1Hochfeld-Magnetlabor Dresden (HLD), Helmholtz-Zentrum Dresden-Rossendorf, D-01314 Dresden, Germany — 2National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA — 3IFW Dresden, Institute for Solid State Research, D-01171 Dresden, Germany
The iron-based compound LiFeAs exhibits superconductivity below Tc ≃ 18 K without introduction of chemical doping. From a number of macroscopic experiments, upper critical fields of 26 T or higher for a magnetic field orientation parallel to the FeAs planes were reported. So far, no local probe techniques were applied for the characterization of the microscopic electronic properties in this high-field parameter regime. We present the results of recently performed high-field NMR experiments on three high quality LiFeAs single crystals, implying upper critical fields much lower than 26 T. We discuss the signatures of the field-induced suppression of the superconducting order parameter, probed by the temperature dependent Knight shift, nuclear spin-lattice and spin-spin relaxation rates for fields and temperatures in the normal and superconducting state.