Anisotropic phase diagram and superconducting fluctuations of single-crystalline SmFeAsO(0.85)F(0.15)

• We report on the specific-heat determination of the anisotropic phase diagram of single crystals of optimally doped SmFeAsO(1-x)F(x). In zero field, we find a clear cusplike anomaly in C/T with Delta C/T(c) = 24 mJ/mol K(2) at T(c) = 49.5 K. In magnetic fields along the c axis, pronounced superconducting fluctuations induce broadening and suppression of the specific-heat anomaly which can be described using three-dimensional lowest-Landau-level scaling with an upper critical field slope of -3.5 T/K and an anisotropy of Gamma = 8. The small value of Delta C/T(c) yields a Sommerfeld coefficient gamma similar to 8 mJ/mol K(2), indicating that SmFeAsO(1-x)F(x) is characterized by a modest density of states and strong coupling.

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NATURVETENSKAP  -- Fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences (hsv//eng)

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ref (subject category)

art (subject category)