Berlin 2012 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 2: Superconductivity: Fe-based Superconductors - 1111, LiFeAs & As-free Pnictides

TT 2.10: Vortrag

Montag, 26. März 2012, 12:00–12:15, H 2053

Electronic Transport Properties of LiFeAs in comparision to Ni-doped and Li-deficient LiFeAs — •Dirk Bombor, Anne Bachmann, Luminita Harnagea, Claudia Nacke, Saicharan Aswaratham, Sabine Wurmehl, Christian Hess, and Bernd Büchner — Leibnitz Institute for Solid State and Materials Research, IFW Dresden, Germany

Electronic transport properties of the unconventional 111-superconductor LiFeAs in comparison with Ni-doped and Li-deficient LiFeAs have been studied. Unlike in other iron arsenide superconductors the stoichiometric LiFeAs doesn’t show any nesting of the Fermi surface and therefore exhibits no spin density wave but even the undoped compound becomes superconducting below 18 K. In contrast to other iron arsenide superconductors we find that doping by substitution of iron with Ni as well as Li-deficiency suppresses superconductivity. Beside this Li-deficient samples show ferromagnetic ordering below 160 K which leads to an enhancement of the unusual negative magnetoresistance. All compounds show a non-monotonic temperature dependence of the Hall coefficient which is discussed.