Pressure effects on the magnetic order of Ba(Fe0.946Co0.054)2As2

ORAL

Abstract

Cobalt substitution for iron in BaFe2As2 produces a superconducting ground state with indications that antiferromagnetism (AFM) and superconductivity (SC) compete for the same itinerant electrons. Partial cobalt substitution changes the relative sizes of the hole- and electron-like fermi surface pockets responsible for AFM in BaFe2As2 with two effects: 1) the magnitude of the ordered moment decreases with increasing cobalt concentration; and 2) beyond a critical concentration commensurate nesting is lost and a small transverse incommensurability appears which maintains long range magnetic order. Magnetic susceptibility and resistivity measurements in applied pressure show suppression of AFM and appearance of SC above 3.5 GPa in BaFe2As2 and, similarly, suppression of AFM and enhancement of SC below 2 GPa in Ba(Fe1–xCox)2As2. Such measurements could not determine if the suppression of AFM via pressure is due to reduced fermi surface nesting, leaving open the question of whether the mechanisms which produce SC in BaFe2As2 and Ba(Fe1–xCox)2As2 are the same.
Results of single crystal neutron diffraction measurements which were performed under applied pressure to track the suppression of AFM order and look for IC spin density wave order in Ba(Fe0.946Co0.054)2As2 will be discussed.

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Presenters

  • Gregory Tucker

    Ecole Polytech Fed de Lausanne

Authors

  • Gregory Tucker

    Ecole Polytech Fed de Lausanne

  • Jonathan White

    Paul Scherrer Institut

  • Sergey Budko

    Ames Laboratory and Iowa State University, Ames Laboratory, Iowa State University, Dept. of Physics and Astronomy, Ames Laboratory/Iowa State University, Ames Laboratory and Iowa State Univ, Iowa State University, Ames Laboratory

  • Paul Canfield

    Ames Laboratory and Iowa State University, Ames Laboratory, Iowa State University, Department of Physics and Astronomy, Iowa State University, Dept. of Physics and Astronomy, Ames Laboratory/Iowa State University, Iowa state university/Ames Laboratory, Ames Laboratory and Iowa State Univ, Iowa State University and Ames Laboratory, Iowa State University/Ames Laboratory, Iowa State University, Iowa State University / Ames Laboratory, Dept. of Physics, Iowa State Univ, Ames Lab, Ames Laboratory U.S. DOE and Department of Physics and Astronomy, Iowa State University, Iowa State Univ, Ames Laboratory, Department of Physics and Astronomy, Ames Laboratory and Iowa State University

  • Andreas Kreyssig

    Ames Laboratory, Iowa State University, Dept. of Physics and Astronomy, Ames Laboratory/Iowa State University, Iowa State University, Ames Laboratory and Iowa State University, Dept. of Physics and Astronomy, Dept. of Physics, Iowa State Univ, Ames Lab

  • Alan Goldman

    Ames Laboratory, Iowa State University, Dept. of Physics and Astronomy, Ames Laboratory/Iowa State University, Iowa State University, Dept. of Physics, Iowa State Univ

  • Robert McQueeney

    Ames Laboratory, Iowa State University, Dept. of Physics and Astronomy, Ames Laboratory/Iowa State University, Iowa State University, Ames Laboratory and Iowa State University, Dept. of Physics and Astronomy