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