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arXiv · 0806.0781

High-Field Pauli-Limiting Behavior and Strongly Enhanced Upper Critical Magnetic Fields near the Transition Temperature of an Arsenic-Deficient LaO_0.9F_0.1FeAs_(1-δ) Superconductor

G. Fuchs·S. -L. Drechsler·N. Kozlova·G. Behr·A. Koehler·J. Werner·K. Nenkov·C. Hess·R. Klingeler·J. E. Hamann-Borrero·A. Kondrat·M. Grobosch·A. Narduzzo·M. Knupfer·J. Freudenberger·B. Buechner·L. Schultz
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Abstract

We report upper critical field B_c2(T) data for disordered (arsenic-deficient) LaO_0.9F_0.1FeAs_(1-delta) in a wide temperature and magnetic field range up to 47 T. Because of the large linear slope of Bc2 about -5.4 T/K to -6.6 T/K near Tc = 28.5 K the T-dependence of the in-plane Bc2(T) shows a flattening near 23 K above 30 T which points to Pauli-limited behavior with Bc2(0) about 63-68 T. Our results are discussed in terms of disorder effects within conventional and unconventional superconducting pairings.

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G. Fuchs, S. -L. Drechsler, N. Kozlova, G. Behr, A. Koehler, J. Werner, K. Nenkov, C. Hess, R. Klingeler, J. E. Hamann-Borrero, A. Kondrat, M. Grobosch, A. Narduzzo, M. Knupfer, J. Freudenberger, B. Buechner, L. Schultz. 2009-02-20. High-Field Pauli-Limiting Behavior and Strongly Enhanced Upper Critical Magnetic Fields near the Transition Temperature of an Arsenic-Deficient LaO_0.9F_0.1FeAs_(1-δ) Superconductor. https://doi.org/10.1103/physrevlett.101.237003

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