Dresden 2014 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 30: Superconductivity - Poster Session
TT 30.32: Poster
Montag, 31. März 2014, 15:00–19:00, P2
Local probe studies at copper containing 111 compounds — •Sirko Kamusella1, Gohil S Thakur2, Zeba Haque2, Ashok K Ganguli2, L C Gupta2, Hubertus Luetkens3, and Hans-Henning Klauss1 — 1Institut für Festkörperphysik, Technische Universität Dresden, 01062 Dresden, Germany — 2Department of Chemistry, Indian Institute of Technology,110016 New Delhi, India — 3Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
The recently synthesized LiFeAs-related compounds CuFeAs and CuFeSb [1] are discussed in terms of bulk measurements,57Fe mössbauer spectroscopy and µSR, comparing it to antiferromagnetic LiFeAs samples. In the compounds presented here the alkali metal sites are replaced by the transition metal copper leading to a stretched Fe-As-bond and therefore deformed As-tetrahedra.
According to these structural differences, CuFeAs and LiFeAs show opposite temperature dependencies of the quadrupolar interaction at the iron site. Furthermore we can confirm the ferromagnetic behavior of CuFeSb [2] up to TN=375 K, but observe long range antiferromagnetic order below 10 K for CuFeAs, similar to Li-111 samples. Both LiFeAs and CuFeAs show an unusual magnetoelastic coupling, which might play an important role for superconductivity in the 111. We discuss doping options to achieve superconductivity and suggest pressure studies to clarify the effect of pnictide spacing on (anti)ferromagnetism.
[1] G. Thakur et al., unpublished
[2] B. Qian et al., Phys. Rev. B. 85 (2012) 144427