Tuesday, April 30, 2013

1304.7416 (Boby Joseph et al.)

Temperature dependent local atomic displacements in Ru substituted
SmFe_{1-x}Ru_{x}AsO_{0.85}F_{0.15} superconductors

Boby Joseph, Antonella Iadecola, Laura Simonelli, Laura Maugeri, Alberto Martinelli, Andrea Palenzona, Marina Putti, Naurang L. Saini
Local structure of SmFe$_{1-x}$Ru$_x$AsO$_{0.85}$F$_{0.15}$ ($x$ = 0.0, 0.05, 0.25 and 0.5) superconductors has been investigated by temperature dependent As $K$-edge extended x-ray absorption fine structure. The effect of Ru substitution remains confined to the iron-arsenide layer but neither the static disorder nor the Fe-As bond strength suffers any change for $x \le$ 0.25. With further Ru substitution the static disorder increases while the Fe-As bond strength remains unchanged. Also, the Ru-As distance ($\sim$2.42 \AA), different from the Fe-As distance ($\sim$2.39 \AA), does not show any change in its force constant with the Ru substitution. These observations suggest that the SmFe$_{1-x}$Ru$_x$AsO$_{0.85}$F$_{0.15}$ system breaks down to coexisting local electronic phases on isoelectric substitution in the active FeAs layer.
View original: http://arxiv.org/abs/1304.7416

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