GERENCIA DE ÁREA INVESTIGACIÓN, DESARROLLO E INNOVACIÓN (GAIDI)

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https://nuclea.cnea.gob.ar/handle/20.500.12553/4400

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Examinando GERENCIA DE ÁREA INVESTIGACIÓN, DESARROLLO E INNOVACIÓN (GAIDI) por Materia "CALCOGENUROS"

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    ÍtemAcceso Abierto
    Influence of the Fe Concentration on the Superconducting Properties of Fe1-ySe
    (Springer, 2015-00-00) Amigó, M.L.; Ale Crivillero, M.V.; Franco, D.G.; Guimpel, J.; Nieva, G.; Gerencia Física. Departamento Materia Condensada. División Bajas Temperaturas
    We present a comparative study of electrical transport properties in the normal state and in the dissipative superconducting state between pure β-FeSe phase and Fe deficient Fe1−y Se crystals. We discuss the influence of the intergrowth of the magnetic hexagonal phase (Fe7 Se8 ) in Fe deficient samples when compared to pure β-FeSe samples. In the superconducting state, we measured the ab-plane electrical resistivity with magnetic field up to 16 T and the electrical resistivity as a function of the angle between the c axis and the applied field. The angular dependence at fixed temperature below the superconducting critical temperature, Tc(H = 0), is very different for both sets of crystals. The Fe deficient samples display a vortex pinning-related feature at ∼57◦ off the plane while the pure β-FeSe phase samples show the persistence of a strong angular-dependent magnetoresistance characteristic of the normal state electronic structure.
  • Miniatura
    ÍtemAcceso Abierto
    Pressure cycle of superconducting Cs0.8Fe2Se2 : A transport study
    (Elsevier, 2011-05-10) Seyfarth, G.; Jaccard, D.; Pedrazzini, P.; Krzton-Maziopa, A.; Pomjakushina, E.; Conder, K.; Shermadini, Z.; Gerencia Física. Departamento Materia Condensada. División Bajas Temperaturas
    We report measurements of the temperature and pressure dependence of the electrical resistivity (ρ) of single-crystalline iron-based chalcogenide Cs0.8Fe2Se2. In this material, superconductivity with a transition temperature (Tc ) ∼ 30 K develops from a normal state with extremely large resistivity. At ambient pressure, a large ‘‘hump’’ in the resistivity is observed around 200 K. Under pressure, the resistivity decreases by two orders of magnitude, concomitant with a sudden Tc suppression around pc ∼ 8 GPa. Even at 9 GPa a metallic resistivity state is not recovered, and the ρ(T ) ‘‘hump’’ is still detected. A comparison of the data measured upon increasing and decreasing the external pressure leads us to suggest that the superconductivity is not related to this hump.