Study of lattice distortion in Sr(Fe$_{1-x}$Co$_{x}$)$_{2}$As$_{2}$ single crystals employing high-energy x-ray diffraction

ORAL

Abstract

For the iron arsenide family of superconductors, the interplay between structure, magnetism, and superconductivity is a major theme of research. Among $A$Fe$_{2}$As$_{2}$ ($A =$ Ca, Sr, Ba), a difference lies in the strength of magnetoelastic coupling: it is strongest in CaFe$_{2}$As$_{2}$ as indicated by strongly coupled first order phase transitions (structural and magnetic) and modest in BaFe$_{2}$As$_{2}$ in which the two phase transitions split with Co-substitution. Moreover, similar to the structural transition, the magnetic transition becomes second order with higher Co-concentration. SrFe$_{2}$As$_{2}$ shows intermediate behavior. Here we present a temperature-dependent study of the lattice distortion from tetragonal to orthorhombic in Sr(Fe$_{1-x}$Co$_{x})_{2}$As$_{2}$ single crystals through diffraction measurements using x-ray radiation of two energies: 8.047 keV and 100 keV. The lower energy probes a few micrometers down from the surface of the sample whereas the higher energy characterizes the bulk. Details of the lattice distortion obtained with these two probes will be discussed.\\[4pt] The work at Ames Laboratory was supported by US DOE, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Contract DE-AC02-07CH11358. This research used resources of Advanced Photon Source, a US DOE, Office of Science User Facility.

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Authors

  • A. Sapkota

    Ames Laboratory US DOE, Department of Physics and Astronomy, Iowa State University

  • W.T. Jayasekara

    Ames Laboratory U.S. DOE and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA, Ames Laboratory US DOE, Department of Physics and Astronomy, Iowa State University

  • Abhisek Pandey

    Ames Laboratory US DOE, Department of Physics and Astronomy, Iowa State University

  • Shree R. Banjara

    Ames Laboratory US DOE, Department of Physics and Astronomy, Iowa State University

  • P. Das

    Ames Laboratory US DOE, Department of Physics and Astronomy, Iowa State University

  • N.S. Sangeetha

    Ames Laboratory U.S. DOE and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA, Ames Laboratory US DOE, Department of Physics and Astronomy, Iowa State University

  • D.C. Johnston

    Ames Laboratory U.S. DOE and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA, Ames Laboratory US DOE, Department of Physics and Astronomy, Iowa State University

  • A. Kreyssig

    Ames Laboratory U.S. DOE and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA, Ames Laboratory US DOE, Department of Physics and Astronomy, Iowa State University

  • A.I. Goldman

    Ames Laboratory and Iowa State University, Ames Laboratory U.S. DOE and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA, Ames Laboratory US DOE, Department of Physics and Astronomy, Iowa State University