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Study of Structural and Magnetotransport Properties of Fe(Te, Se) Single Crystals
Author(s) -
Kumar Rohit,
Varma Ghanshyam Das
Publication year - 2020
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201900552
Subject(s) - condensed matter physics , vortex , superconductivity , materials science , flux pinning , arrhenius equation , magnetic field , vortex state , single crystal , pinning force , flux (metallurgy) , magnetic flux , field (mathematics) , activation energy , physics , thermodynamics , high temperature superconductivity , chemistry , nuclear magnetic resonance , critical current , organic chemistry , quantum mechanics , mathematics , pure mathematics , metallurgy
Single‐crystalline samples of nominal compositions FeTe 0.88 and FeTe 1− x Se x are synthesized using the self‐flux method. The activation energy of the flux flow is estimated using the Arrhenius relation as well as by the modified thermally activated flux flow (TAFF) model. The field dependence of U 0 shows transition from single to collective vortex pinning at a magnetic field of ≈2 T. The analysis of field‐dependent U 0 data reveals the planar and the point defect magnetic field regions for both the models. The modified TAFF model is used to study the 2D and 3D behavior of the vortex state for all the superconducting samples. The single‐crystalline FeTe 0.80 Se 0.20 and FeTe 0.60 Se 0.40 samples show 3D behavior, whereas the FeTe 0.40 Se 0.60 crystal shows 2D behavior. The vortex phase diagrams of all the superconducting samples are obtained by analyzing the magnetotransport data. The vortex phase diagrams reveal transitions from the unpinned to pinned vortex liquid state and the vortex liquid to vortex glass state. Below T *, the critical exponent s is in good agreement with q values for 2D/3D behavior of vortex states of all the superconducting samples.