Pressure and chemical substitution effects in the local atomic structure of BaFe2As2

Abstract

The effects of K and Co substitutions and quasi-hydrostatic applied pressure (P<9 GPa) in the local atomic structure of BaFe2As2, Ba(Fe{0.937}Co{0.063})2As2 and Ba{0.85}K{0.15}Fe2As2 superconductors were investigated by extended x-ray absorption fine structure (EXAFS) measurements in the As K absorption edge. The As-Fe bond length is found to be slightly reduced (<~ 0.01 Angstroms) by both Co and K substitutions, without any observable increment in the corresponding Debye Waller factor. Also, this bond is shown to be compressible (k = 3.3(3)x10^{-3} GPa^{-1}). The observed contractions of As-Fe bond under pressure and chemical substitutions are likely related with a reduction of the local Fe magnetic moments, and should be an important tuning parameter in the phase diagrams of the Fe-based superconductors.

7 pages, 6 figures

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Cited by in corpus (13)

• High-pressure flux growth, structural, and superconducting properties of LnFeAsO (Ln = Pr, Nd, Sm) single crystals
• Co-substitution effects on the Fe-valence in the BaFe2As2 superconducting compound: A study of hard x-ray absorption spectroscopy
• Quantum criticality in AFe2As2 with A = K, Rb, and Cs suppresses superconductivity
• Uniaxial versus hydrostatic pressure-induced phase transitions in CaFe2As2 and BaFe2As2
• Complex structures of different CaFe${}_2$As${}_2$ samples
• Universal pair-breaking in transition metal-substituted iron-pnictide superconductors
• Possible unconventional superconductivity in substituted BaFe${}_2$As${}_2$ revealed by magnetic pair-breaking studies
• Importance of structural distortions in enhancement of transition temperature in FeSe${}_{1-x}$Te${}_x$ superconductors
• Orbital localization and the role of the Fe and As $4p$ orbitals in BaFe${}_2$As${}_2$ probed by XANES
• Local structural distortions and their role in superconductivity in SmFeAsO${}_{1-x}$F${}_x$ superconductors
• Quantum Oscillations in EuFe2As2 single crystals
• Hard X-ray spectroscopy of the itinerant magnets $R$Fe${}_4$Sb${}_{12}$ ($R=$Na, K, Ca, Sr, Ba)
• Filling the holes in the CaFe${}_4$As${}_3$ structure: synthesis and magnetism of CaCo${}_5$As${}_3$