The effect of Ru substitution on the local structure of layered SmFe1-xRuxAsO0.85F0.15 superconductor has been studied by As K- and Sm L-3-edge x-ray-absorption spectroscopy. The extended x-ray-absorption fine-structure measurements reveal distinct Fe-As and Ru-As bond lengths in the Ru substituted samples with the latter being similar to 0.03 angstrom longer. Local disorder induced by the Ru substitution is mainly confined to the FeAs layer while the SmO spacer layer sustains a relative order, consistent with the x-ray-absorption near-edge structure spectra. The results suggest that, in addition to the order/disorder in the active FeAs layer, its coupling to the rare-earth-oxygen spacer layer needs to be considered for describing the electronic properties of these layered superconductors.
Effect of Ru substitution on atomic displacements in the layered SmFe_{1−x}Ru_{x}AsO_{0.85}F_{0.15} superconductor
PUTTI, MARINA;
2012-01-01
Abstract
The effect of Ru substitution on the local structure of layered SmFe1-xRuxAsO0.85F0.15 superconductor has been studied by As K- and Sm L-3-edge x-ray-absorption spectroscopy. The extended x-ray-absorption fine-structure measurements reveal distinct Fe-As and Ru-As bond lengths in the Ru substituted samples with the latter being similar to 0.03 angstrom longer. Local disorder induced by the Ru substitution is mainly confined to the FeAs layer while the SmO spacer layer sustains a relative order, consistent with the x-ray-absorption near-edge structure spectra. The results suggest that, in addition to the order/disorder in the active FeAs layer, its coupling to the rare-earth-oxygen spacer layer needs to be considered for describing the electronic properties of these layered superconductors.
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