Dresden 2014 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 45: Superconductivity: Fe-based Superconductors - 1111,111, FeSe

TT 45.7: Vortrag

Dienstag, 1. April 2014, 15:30–15:45, HSZ 201

Magnetoresistance and Hall effect of Fe_1.01Se — •Sahana Roessler, Cevriye Koz, Ulrich Schwarz, and Steffen Wirth — Max Planck Institute for Chemical Physics of Solids, Noethnitzer Str. 40, 01187 Dresden

The simplest member of Fe-based superconductor Fe_1.01Se displays a superconducting transition at T_c ≈ 8 K [1] and a structural transition at T_s ≈ 90 K [2]. Here we present magnetoresistance, Hall effect, and magnetic susceptibility of Fe_1.01Se single crystals. The onset of negative magnetoresistance below T_s indicates a strong change to the Fermi surface topology at the structural phase transition. The Hall resistivity ρ_xy is negative below 55 K indicating electron dominated transport, and non-linear in magnetic field down to 12 K. The magnetic susceptibility also displays a minimum close to 30 K suggesting a strong enhancement of antiferromagnetic fluctuations. This behavior is in agreement with the temperature dependence of spin-fluctuation susceptibility in NMR measurements [3]. These results suggest that the pairing correlations in Fe_1.01Se are enhanced by antiferromagnetic fluctuations.
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