$\mu$SR Studies of Electron-doped 122 Pnictide Superconductors

ORAL

Abstract

Single crystals of Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$ and Sr(Fe$_{1-x}$Co$_x$)$_2$As$_2$ were studied using Transverse field (TF)-$\mu$SR. We measured the penetration depth in the superconducting state by fitting the $\mu$SR spectra to a microscopic model for a range of applied magnetic fields and dopings. We have fit the temperature dependence of the superfluid density to a phenomenological two-gap model. We find that the low-temperature superfluid density varies roughly linearly with superconducting T$_C$, both of which decrease with increasing Co substitution above x = 0.06.

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Authors

  • Travis Williams

    • McMaster University

  • A.A. Aczel

    • McMaster University

  • J.P. Carlo

    • Columbia University

  • Y.J. Uemura

    • Columbia University

  • J. Paglione

    • University of Maryland

  • S.L. Bud'ko

    • Ames Laboratory, Iowa State University

  • N. Ni

    • Ames Laboratory, Iowa State University

  • P.C. Canfield

    • Ames Laboratory, Iowa State University

  • T. Goko

    • McMaster University, Columbia University, TRIUMF

  • G.M. Luke

    • McMaster University