1206.6526 (A. Iadecola et al.)

Effect of Ru susbstitution on atomic displacements in the layered
SmFe_{1-x}Ru_xAsO_{0.85}F_{0.15} superconductor    [PDF]

A. Iadecola, B. Joseph, L. Simonelli, L. Maugeri, M. Fratini, A. Martinelli, A. Palenzona, M. Putti, N. L. Saini

The effect of Ru substitution on the local structure of layered SmFe$_{1-x}$Ru$_x$AsO$_{0.85}$F$_{0.15}$ superconductor has been studied by As $K$- and Sm $L_3$ - edges x-ray-absorption spectroscopy. The extended x-ray-absorption fine-structure measurements reveal distinct Fe-As and Ru-As bondlengths in the Ru substituted samples with the latter being $\sim$0.03 \AA\ 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 active iron-arsenide layer, its coupling to the rare-earth\textminus oxygen spacer layer needs to be considered for describing the electronic properties of these layered superconductors.

View original: http://arxiv.org/abs/1206.6526