Berlin 2012 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 33: Superconductivity, Measuring Devices, Matter at Low Temperature: Poster Session
TT 33.19: Poster
Mittwoch, 28. März 2012, 15:00–19:00, Poster B
Mössbauer investigation of magnetic and structural phase transitions in Fe1+xTe — •Philipp Materne1, Cevriye Coz2, Sahana Rössler2, Ulrich K. Rössler3, Mathias Doerr1, Steffen Wirth2, Ulrich Schwarz2, Til Goltz1, and Hans-Henning Klauß1 — 1Institut für Festkörperphysik, Technische Universität Dresden, 01062 Dresden, Germany — 2Max Planck Institute for Chemical Physics of Solids, Nöthnizer Straße 40, 01187, Dresden, Germany — 3IFW Dresden, Postfach 270016, 01171 Dresden, Germany
Fe1+xTe, the antiferromagnetic parent compound of the
Fe-chalcogenide superconductors, displays separated magnetic
(TN) and structural (Ts) transitions with
TN > Ts for x > 0.12 [1]. Such behavior,
namely the magnetic transition preceeding the structural
transition upon cooling, is uncommon for the parent
systems of pnictide superconductors. We performed
Mössbauer spectroscopy on samples with two representative levels
of iron excess: i) Fe1.06Te with simultaneous magnetic
and structural transitions at TN = Ts =69 K and
ii) Fe1.13Te with separated transitions at TN = 57 K followed by Ts = 46 K. Mössbauer data, analyzed by taking into account two different Fe-sites clearly, display a precursor magnetic state which is only present in Fe1.13Te. Further, a complex magnetic phase has been observed in the temperature range 75 K ≳ T ≳ 40 K in Fe1.13Te. We discuss our Mössbauer results in the context of recently published thermodynamic and neutron scattering
data on Fe1+xTe.
S. Rößler et al., Phys. Rev. B.
84 (2011) 174506.