Abstract
The effects of K and Co substitutions and quasihydrostatic applied pressure ( GPa) in the local atomic structure of BaFeAs, Ba(FeCo)As and BaKFeAs superconductors were investigated by extended x-ray absorption fine structure (EXAFS) measurements in the As absorption edge. The As-Fe bond length is found to be slightly reduced ( Å) by both Co and K substitutions, without any observable increment in the corresponding Debye-Waller factor. Also, this bond is shown to be compressible [ GPa]. 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.
- Received 2 February 2011
DOI:https://doi.org/10.1103/PhysRevB.83.184508
©2011 American Physical Society