Berlin 2012 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 33: Superconductivity, Measuring Devices, Matter at Low Temperature: Poster Session

TT 33.20: Poster

Wednesday, March 28, 2012, 15:00–19:00, Poster B

Noise spectroscopy of superconducting systems δ^′-FeSe and FeSe_0.5Te_0.5 — •Adham Amyan¹, Amir-Abbas Haghighirad¹, Pintu Das¹, Sahana Rößler², Steffen Wirth², Dona Cherian³, Suja Elizabeth³, Wolf Aßmus¹, and Jens Müller¹ — ¹Physikalisches Institut, Goethe-Universität Frankfurt, Frankfurt am Main, Germany — ²Max-Planck-Institute for Chemical Physics of Solids, Dresden, Germany — ³Dep. of Physics, Indian Institute of Science, Bangalore, India

One of the most recent interesting and surprising phenomena is superconductivity in Fe-based compound (i.e. pnictides and chalcogenides), where FeSe has the most simple structure of the diverse family of these materials. The FeSe_1−xTe_x system shows superconductivity up to T_c∼ 14 K. The Fe planar structure may be crucial for understanding the mechanism of superconductivity in these systems: it was suggested that a low temperature structural distortion is closely associated with the superconductiing properties of this material [1]. We employ fluctuation (noise) spectroscopy to study the intrinsic charge carriers dynamics and their correlation with the structural properties. In both superconducting compounds δ^′-FeSe and FeSe_0.5Te_0.5 we observe a maximum in the normalized noise power spectral density at 107 K and 110 K respectively, where a structural transition from tetragonal to orthorhombic occurs [2].
M. J. Wang et al, PRL 103, 117002 (2009)
M. de Souza et al, Eur. Phys. J. B 77, 101-107 (2010)