Regensburg 2010 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 39: SC: Iron-Based Superconductors - 1111

TT 39.5: Vortrag

Freitag, 26. März 2010, 11:30–11:45, H19

Structural transition and magnetic ordering in
(Sm,Ce)FeAsO_(1−x)F_x — •Jorge E. Hamann-Borrero¹, Agnieszka Kondrat¹, Hemke Maeter², Ralf Feyerherm³, Hans-Henning Klauss², Ruediger Klingeler¹, Christian Hess¹, Guenther Behr¹, Dimitri Argyriou³, and Bernd Buechner¹ — ¹Leibniz Institute for Solid State and Materials Research, IFW Dresden, 01171 Dresden, Germany — ²Institut fuer Festkoerperphysik, TU Dresden, D-01069 Dresden, Germany — ³Helmholtz Zentrum Berlin. Albert Einstein Str.15 12489 Berlin

The tetragonal to orthorhombic transition of the layered compounds (Sm,Ce)FeAsO_(1−x)F_x is studied by means of synchrotron x-ray diffraction, µSR and resistivity. We particularly focus on the onset of the SDW and superconducting states by monitoring the structural transition temperature T_s the magnetic ordering temperature T_N and the critical temperature T_c. In the case of SmFeAsO_(1−x)F_x the SDW state is only gradually suppressed upon doping until it is entirely suppressed in favour of the superconducting state. This is in contrast to CeFeAsO_(1−x)F_x where the SDW state is suppressed much more efficiently and where superconductivity coexists with magnetism. Moreover, in further contrast to the findings by Zhao et al [1], we do not observe any orthorhombic distortion in superconducting samples.

[1] Zhao et al. Nature Materials, 2008, 7, 953-959.