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$_2$.

*Supported by NSF through grant DMR-0804887. Work at Ames Lab oratory is supported by the U. S. DOE, Basic Energy Sciences under Contract No. DE-AC02-07CH11358.

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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