Small-angle neutron scattering study of vortex matter in superconducting Ba(Fe$_{0.93}$Co$_{0.07}$)$_2$As$_2$

ORAL

Abstract

We present small-angle neutron scattering studies of the superconducting vortices Ba(Fe$_{0.93}$Co$_{0.07}$)$_2$As$_2$. At all fields measured a ring of scattering was observed, indicating a highly disordered vortex configuration, and no discernable rocking curve could be measured. The field dependence of the magnitude of the scattering vector indicates vortex lattice domains of (distorted) hexagonal symmetry. An analysis of the scattered intensity due to the vortices shows a rapid decrease with increasing applied magnetic field, significantly exceeding what would be expected based on estimates of the upper critical field. These results are consistent with the existence of a vortex glass or Bragg glass phase in Ba(Fe$_{0.93}$Co$_{0.07}$)$_2$As$_2$.

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Authors

  • M. R. Eskildsen

    University of Notre Dame, IN, USA, University of Notre Dame

  • T. Blasius

    University of Michigan

  • Alan Goldman

    Ames Laboratory and Physics Department and Astronomy, Iowa State University, Ames, IA, Ames Laboratory and Iowa State University, Ames Laboratory, US DOE and Iowa State University, Ames Laboratory, Ames Loboratory, US DOE and Iowa State University, Ames Laboratory/Department of Physics and Astronomy, Ames Laboratory, US DOE, Iowa State University, Ames, IA 5001, USA

  • J. M. Densmore

    University of Notre Dame

  • C. D. Dewhurst

    Institut Laue-Langevin

  • N. Ni

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

  • Andreas Kreyssig

    Ames Laboratory and Physics Department and Astronomy, Iowa State University, Ames, IA, Ames Laboratory and Iowa State University, Ames Laboratory, US DOE and Iowa State University, Ames Laboratory/Department of Physics and Astronomy, Ames Laboratory, US DOE, Iowa State University, Ames, IA 5001, USA

  • S.L. Bud'ko

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

  • P.C. Canfield

    Ames Laboratory and Department of Physics and Astronomy, Iowa State Univeristy, Ames, Iowa 50011, Ames Laboratory and Iowa State University, Ames Laboratory and Physics Department and Astronomy, Iowa State University, Ames, IA, Ames Laboratory, Ames Laboratory, US DOE and Iowa State University, Ames Laboratory/Department of Physics and Astronomy, Ames Lab / Iowa State University, Ames Laboratory/Iowa State University