A study of temperature dependent local atomic displacements in a Ba(Fe1-xCox)2As2 superconductor

M. Y. Hacisalihoglu, E. Paris, B. Joseph, L. Simonelli, T. J. Sato, Takashi Mizokawa, N. L. Saini

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    6 Citations (Scopus)

    Abstract

    We have studied the local structure of a Ba(Fe1-xCox)2As2 superconductor using temperature dependent extended X-ray absorption fine structure (EXAFS) measurements. Polarized EXAFS at the Fe K-edge on an optimally doped (x = 0.06) single crystal has permitted us to determine atomic displacements across the superconducting transition temperature (Tc). The Fe-As bondlength hardly shows any change with temperature; however, the Fe-Fe sublattice reveals a sharp anomaly across Tc, indicated by a significant drop in mean square relative displacements, similar to the one known for cuprates and A15-type superconductors. We have also found a large atomic disorder around the substituted Co, revealed by polarized Co K-edge EXAFS measurements. The Co-Fe/Co bonds are more flexible than the Fe-Fe bonds with the As-height in Co-containing tetrahedra being larger than the one in FeAs4. The results suggest that the local Fe-Fe bondlength fluctuations and the atomic disorder in this sub-lattice should have some important role in the superconductivity of Ba(Fe1-xCox)2As2 pnictides.

    Original languageEnglish
    Pages (from-to)9029-9035
    Number of pages7
    JournalPhysical Chemistry Chemical Physics
    Volume18
    Issue number13
    DOIs
    Publication statusPublished - 2016 Apr 7

    ASJC Scopus subject areas

    • Physical and Theoretical Chemistry
    • Physics and Astronomy(all)

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