Berlin 2012 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 8: Superconductivity: Fe-based Superconductors - 122 Part 1

TT 8.11: Vortrag

Montag, 26. März 2012, 17:45–18:00, H 2053

Enhancement of the upper critical field in codoped iron-arsenic high-temperature superconductors — •H. Rosner¹, M. Nicklas¹, W. Schnelle¹, A. Leithe-Jasper¹, J. Wosnitza², and F. Weickert^1,3 — ¹MPI CPfS Dresden — ²HLD Dresden-Rossendorf — ³LANL Los Alamos

We present the first study of codoped iron-arsenide superconductors of the 122 family (Sr/Ba)_1−xK_xFe_2−yCo_yAs₂ with the purpose to increase the upper critical field H_c2 compared to single doped Sr/BaFe₂As₂ materials. H_c2 was investigated by measuring the magnetoresistance in high pulsed magnetic fields up to 64 T. We find, that H_c2 extrapolated to T = 0 is indeed enhanced significantly to 90 T for polycrystalline samples of Ba_0.55K_0.45Fe_1.95Co_0.05As₂ compared to 75 T for Ba_0.55K_0.45Fe₂As₂ and BaFe_1.8Co_0.2As₂ single crystals. Codoping thus is a promising way for the systematic optimization of iron-arsenic based superconductors for magnetic-field and high-current applications.