Effects of Ru Doping on the Transport Behavior and Superconducting Transition Temperature of NdFeAsO0.89F0.11

The transport behavior and superconducting transition temperature Tc of NdFe1-yRuyAsO0.89F0.11 have been studied for various y values. Because Ru impurities are isoelectronic to host Fe atoms, we basically expect that the number of electrons does not change with y, at least in the region of small y values. The results indicate that the rate of Tc suppression by Ru atoms is too small to be explained by the pair breaking effect of nonmagnetic impurities expected for the S+- symmetry, confirming our previous results for Co doping.