Unusual superconducting state in Pr-doped CaFe$_{2}$As$_{2}$

ORAL

Abstract

We report the detection of unusual superconductivity up to 49 K in Pr-doped single crystalline CaFe$_{2}$As$_{2}$ as evidenced from the resistive, magnetic and thermoelectric measurements. This superconducting transition observed suggests the possible existence of two phases: a field as low as 500 Oe can totally suppress the observed diamagnetic susceptibility above 21K. The 49 K part has a low critical field $<$ 4 Oe, and the other at 21K, with a high upper critical field $>$ 5T. Our observations are in strong contrast to previous reports of doping or pressurizing layered compounds AeFe$_{2}$As$_{2}$ (Ae122), where Ae = Ca, Sr, or Ba. In Ae 122, hole-doping has been previously observed to generate superconductivity with a transition temperature (Tc) only up to 38 K and pressurization has been reported to produce superconductivity with a Tc up to 30 K. The experiment results of resistivity and inductance measurements of Pr-doped Ca122 under pressure up to 2.0 GPa will also be discussed.

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Authors

  • Liangzi Deng

    • Dept. of Physics at the University of Houston and TcSUH
    • TCSUH and Department of Physics, University of Houston
    • Texas Center for Superconductivity, University of Houston, Houston TX 77204-­5002, USA

  • Bing Lv

    • Dept. of Physics at the University of Houston and TcSUH

  • Melissa Gooch

    • Dept. of Physics at the University of Houston and TcSUH

  • Fengyan Wei

    • Dept. of Physics at the University of Houston and TcSUH

  • Yanyi Sun

    • Dept. of Physics at the University of Houston and TcSUH

  • James Meen

    • Dept. of Chemistry at the University of Houston and TcSUH

  • Yuyi Xue

    • Dept. of Physics at the University of Houston and TcSUH

  • Bernd Lorenz

    • Dept. of Physics at the University of Houston and TcSUH

  • Ching-Wu Chu

    • Dept. of Physics at the University of Houston and TcSUH, Lawrence Berkeley National Laboratory