Berlin 2012 – scientific programme

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TT: Fachverband Tiefe Temperaturen

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

TT 8.9: Talk

Monday, March 26, 2012, 17:15–17:30, H 2053

Microscopic interplay of superconducting and magnetic order parameters in ferropnictides — •H. Maeter¹, T. Goltz¹, J. Spehling¹, H.-H. Klauss¹, M. Bendele², H. Luetkens², R. Khasanov², G. Pascua², Z. Shermadini², A. Amato², S. Aswartham³, J. E. Hamann-Borrero³, A. Kondrat³, C. Hess³, A. Wolter³, S. Wurmehl³, G. Behr³, B. Büchner³, E. Wiesenmayer⁴, D. Johrendt⁴, H. Potts⁵, and B. Banusch⁵ — ¹Institut für Festkörperphysik, TU Dresden, Germany — ²Laboratory for Muon-Spin Spectroscopy, Paul Scherrer Institut, Villigen, Switzerland — ³Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden,Germany — ⁴Department Chemie, Ludwig-Maximilians-Universität München, Germany — ⁵Swiss Nanoscience Institute, Universität Basel, Switzerland

We present results of µSR experiments of Ba_1−xNa_xFe₂As₂ that show a large coupling of the superconducting and magnetic order parameters. This is unexpected in light of the phase separation in Ba_1−xK_xFe₂As₂. However, in a µSR study of Ba_1−xK_xFe₂As₂ we unambiguously showed microscopic coexistence, even though there are many reports of phase separation in this system [1]. In FeSe_1−x the interplay of phase separation and microscopic coexistence is also evident, here pressure can induce a change from microscopic coexistence to a combination of both [2]. In light of the µSR results it seems likely that phase separation and microscopic coexistence depend on the microscopic properties much more than on disorder.
Wiesenmayer et al., Phys. Rev. Lett. 107, 237001 (2011);
Bendele et al., Phys. Rev. Lett. 104, 087003 (2010).