Doping evolution of the anisotropic upper critical field in (Ba$_{1-x}$K$_x$)Fe$_2$As$_2$

ORAL

Abstract

The temperature and magnetic field- dependent in-plane resistivity measurements were used to determine anisotropic upper critical field, $H_{c2}(T)$, of the hole-doped iron-based superconductor (Ba$_{1-x}$K$_x$)Fe$_2$As$_2$ over the whole doping range $x$=0 to $x$=1. We find clear saturation of $H_{c2}(T)$ line on $T \to 0$ in magnetic field perpendicular to the $c$-axis of the samples in the overdoped range of the phase diagram, suggesting strong paramagnetic limiting effects. Measurements reveal clear difference in the shapes of the $H_{c2}(T)$ lines for under-doped and over-doped compositions with similar $T_c$. Origin of this difference will be discussed.

*This work was supported by the Department of Energy Office of Science, Basic Energy Sciences under Contract No. DE-AC02-O7CH11358.

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Authors

  • Makariy Tanatar

    • Ames Laboratory USDOE, Ames, IA 50011
    • Ames Laboratory and Iowa State University, USA
    • Ames laboratory and Department of Physics and Astronomy, Iowa State University

  • Yong Liu

    • Ames Laboratory USDOE, Ames, IA 50011
    • Ames Laboratory and Iowa State University, USA
    • Division of Materials Sciences and Engineering, Ames Lab., US DOE, Ames, IA 50011
    • Max-Planck-Institut fuer Festkoerperforschung

  • T.A. Lograsso

    • Ames Laboratory USDOE, Ames, IA 50011

  • Ruslan Prozorov

    • Ames Laboratory USDOE, Ames, IA 50011

  • Jan J. Jaroszynski

    • National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA

  • J.S. Brooks

    • National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA