Tetragonal-to-orthorhombic lattice distortion and domains in Ca(Fe$_{1-x}$Co$_x$)$_2$As$_2$ single crystals

ORAL

Abstract

Similarly to other Fe-based pnictide superconductors, Ca(Fe$_{1-x}$Co$_x$)$_2$As$_2$ single crystals show a tetragonal-to-orthorhombic lattice distortion that is suppressed with increasing Co concentration. However, in contrast to other Fe-based pnictide superconductors, an unprecedented 45$^\circ$ rotation of the domain patterns in polarized-light microscopic studies has been observed for Co concentrations $x\,\approx\,0.2$ at temperatures around the onset of antiferromagnetic order and lattice distortion. We present a high-resolution high-energy x-ray diffraction study demonstrating that the observed change in domain arrangement is related to the coexistence of the tetragonal and orthorhombic phases in a well-defined geometric configuration allowed by a special relationship between the lattice parameters of both phases in these compounds. \\[4pt] The work at the Ames Laboratory was supported by US DOE, Office of Basic Energy Sciences, Department of Materials Sciences and Engineering under contract DE-AC02-07CH11358. This research used resources of the Advanced Photon Source, a US DOE, Office of Science User Facility.

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Authors

  • 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

  • E.C. Blomberg

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

  • G.S. Tucker

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

  • A. Sapkota

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

  • S. Ran

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

  • S.L. Bud'ko

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

  • P.C. Canfield

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

  • M.A. Tanatar

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

  • R. Prozorov

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

  • A.I. Goldman

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