Inducing structural collapse and superconductivity in CaFe$_{2}$As$_{2}$ by systematic substitutions of rare earths

ORAL

Abstract

Recently, we have reported structural collapse and 47 K superconductivity in CaFe$_{2}$As$_{2}$ by aliovalent rare earth substitutions for Ca atoms [1]. We will present the evolution of structural and superconducting properties in single crystals of CaFe$_{2}$As$_{2}$ by systematic substitutions of R (=La, Ce, Pr, and Nd) for Ca, causing electron doping that is indirect to FeAs layer. Effect of annealing, growth method, etching, and pressure on Ca$_{1-x}$R$_{x}$Fe$_{2}$As$_{2}$, indicating the intrinsic nature of this high Tc superconductivity, the highest in 122 Fe-based materials, will be discussed. Ref. [1] S. R. Saha \textit{et al}. arXiv:1105.4798.

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Authors

  • Shanta Saha

    • Center for Nanophysics and Advanced Materials, Department of Physics, University of Maryland-College Park
    • Center for Nanophysics and Advanced Materials, Dept. of Physics, University of Maryland, College Park, MD 20742
    • Center for Nanophysics \& Advanced Materials and Department of Physics, University of Maryland

  • Tyler Drye

    • Center for Nanophysics and Advanced Materials, Department of Physics, University of Maryland-College Park
    • Center for Nanophysics and Advanced Materials, Dept. of Physics, University of Maryland, College Park, MD 20742

  • Nicholas Butch

    • Lawrence Livermore National Laboratory
    • Center for Nanophysics and Advanced Materials, Dept. of Physics, University of Maryland, College Park, MD 20742
    • University of Maryland

  • Rongwei Hu

    • Center for Nanophysics and Advanced Materials, Dept. of Physics, University of Maryland, College Park, MD 20742
    • Center for Nanophysics \& Advanced Materials and Department of Physics, University of Maryland

  • Kevin Kirshenbaum

    • Center for Nanophysics and Advanced Materials, Dept. of Physics, University of Maryland, College Park, MD 20742
    • University of Maryland
    • Center for Nanophysics and Advanced Materials, Physics Dept., University of Maryland

  • Steven Ziemak

    • Center for Nanophysics and Advanced Materials, Dept. of Physics, University of Maryland, College Park, MD 20742
    • University of Maryland

  • Johnpierre Palione

    • University of Maryland
    • Center for Nanophysics and Advanced Materials, Department of Physics, University of Maryland-College Park
    • Center for Nanophysics and Advanced Materials, Dept. of Physics, University of Maryland, College Park, MD 20742
    • University of Maryland, College Park
    • Center for Nanophysics and Advanced Materials, Department of Physics, University of Maryland, College Park, Maryland 20742, USA
    • Center for Nanophysics and Advanced Materials, Physics Dept., University of Maryland
    • Center for Nanophysics \& Advanced Materials and Department of Physics, University of Maryland

  • Peter Zavalij

    • Dept. of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742

  • Jeffrey Lynn

    • NIST Center for Neutron Research, Gaithersburg, MD 20899