Berlin 2015 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 52: Superconductivity: Fe-based Superconductors – FeSe and others
TT 52.2: Vortrag
Mittwoch, 18. März 2015, 09:45–10:00, H 2053
Local probe study of superconductivity and ferromagnetism coexisting in Li-intercalated FeSe — •Sirko Kamusella1, Ursula Pachmayr2, Fabian Nitsche2, Felix Brückner1, Hubertus Luetkens3, Rajib Sarkar1, Hans-Henning Klauss1, and Dirk Johrendt2 — 1Institut für Festkörperphysik, Technische Universität Dresden, 01062 Dresden, Germany — 2Department Chemie, Ludwig-Maximilians-Universität München, 81377 München, Germany — 3Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
The intercalated [(Li1−xFex)OH](Fe1−yLiy)Se exhibits superconductivity with Tc=43 K and ferromagnetic order of iron moments within the Interlayer at Tfm≈ 10 K. Similar to P-substituted Eu-122 [1] both ordering phenomena are spatially separated and Tc>Tfm, but in this compound ferromagnetism arises from 3d-electrons and thus offers huge potential to chemically influence the ferromagnetism and further study coexistence in the iron based superconductors.
Our DFT calculation reveals that the hydroxide layers electron-dope the FeSe layer, but do not disturb its typical Fermi surface topology. Instead, the interlayer’s dipolar field continuously penetrates the superconducting volume below 10 K.
Our 57Fe-Mössbauer spectroscopy, 7Li-NMR and µSR data show the interplay of both ordering phenomena and distinguish their origin. Our combined results [2] show, that [(Li1−xFex)OH](Fe1−yLiy)Se is a rare sample of the formation of a spontaneous vortex phase.
[1] T. Goltz, arXiv:1406.7715.
[2] U. Pachmayr et al., Angewandte Chemie (2014).