Evidence for dominant Pauli paramagnetic effect in the upper critical field of single-crystalline FeTe0.6 Se0.4

Seunghyun Khim, Jae Wook Kim, Eun Sang Choi, Yunkyu Bang, Minoru Nohara, Hidenori Takagi, Kee Hoon Kim

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    90 Citations (Scopus)

    Abstract

    We investigated the temperature dependence of the upper critical fields Hc2 (T) of a superconducting FeTe0.6 Se0.4 single crystal by measuring its resistivity in static magnetic fields up to 45 T. Our observations of strong bending in the Hc2ab (T) curves and a nearly isotropic Hc2ab (0) ≈ Hc2c (0) ≈ 48 T support the presence of a strong Pauli paramagnetic effect. We show that the Werthamer-Helfand-Hohenberg formula that includes both the Pauli limiting and the spin-orbit scattering can effectively describe both the H c2ab (T) and Hc2c (T) curves. An enhancement in the quasiparticle density of states or the increased scattering resulting from Te(Se) vacancies or excess Fe is discussed as a possible origin for the manifesting Pauli paramagnetic effect.

    Original languageEnglish
    Article number184511
    JournalPhysical Review B - Condensed Matter and Materials Physics
    Volume81
    Issue number18
    DOIs
    Publication statusPublished - May 14 2010

    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Condensed Matter Physics

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