Berlin 2012 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
TT: Fachverband Tiefe Temperaturen
TT 2: Superconductivity: Fe-based Superconductors - 1111, LiFeAs & As-free Pnictides
TT 2.2: Vortrag
Montag, 26. März 2012, 09:45–10:00, H 2053
75As NQR investigations of charge inhomogeneities in CeFe1−xCoxAsO — •Eva Maria Brüning, Guillaume Lang, Hans-Joachim Grafe, Louis Veyrat, Sabine Wurmehl, and Bernd Büchner — Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden
In the iron pnictides superconductors, carrier doping plays a crucial role in the appearance of superconductivity, whereas the magnetic and the structural phase transitions are suppressed. This is for example the case in LaFeAsO1−xFx [1]. NQR measurements on LnFeAsO1−xFx (Ln = La, Sm) showed in the underdoped region the coexistence of two charge environments at the nanoscale; they point to local electronic order in the iron layers [2]. Surprisingly, in LaFeAsO and SmFeAsO, superconductivity could be successfully induced by cobalt substitution in place of iron which shows that in-plane disorder is highly tolerated in these compounds [3], as in 122 pnictides. This is in high contrast to the cuprate high-Tc superconductors where replacing Cu by other transition metals (Zn, Ni) leads to a suppression of superconductivity. We report on 75As NQR investigations of CeFe1−xCoxAsO (x=0.03, 0.05, 0.07) and the comparison of in-plane Co-doping and out-of-plane F-doping.
[1] Y. Kamihara. al., Chem. Soc. 130, 3296 (2008)
[2] G. Lang et. al., Phys Rev. Lett. 104, 097001 (2010)
[3] C. Wang et. al., Phys Rev. B 79, 054521 (2009)