Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 98: Poster Session: Superconductivity
TT 98.9: Poster
Donnerstag, 15. März 2018, 15:00–19:00, Poster B
ω/T Scaling in Optimal Co-Doped BaFe2As2 — •Jakob Burgi1, Florian Waßer1, Chul-Ho Lee2, Kunihiro Kihou2, Jitae Park3, and Markus Braden1 — 1II. Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, D-50937 Köln, Germany — 2National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568, Japan — 3Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universitä München, Lichtenbergstr. 1, D-85748, Garching, Germany
The phase diagram of iron-based superconductors, in particular of BaFe2As2, indicates the existence of a quantum critical point (QCP) beneath the superconducting (SC) dome, where Tc is highest and the antiferromagnetic (AFM) phase terminates.
Considering an AFM order parameter the associated susceptibility follows a simple scaling relation χ″(qAFM,ω,T) = T−αf(ω/T−α) within the Hertz-Millis scenario.
In this regard, we performed inelastic neutron scattering experiments on 6 % Co doped BaFe2As2 (Tc = 24 K)
and showed that magnetic fluctuations between 28 K and 400 K follow the scaling relation and thus indicate the presence of a QCP.
Our observations are similar to the heavy fermion system CeCu5.9Au0.1 as the scaling function for both compounds seems well approximated by a simple mean-field approach.
Moreover, the scaling law seems to be applicable over the nematic regime without any impact indicating that the nematic transition just follows the magnetic.