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

The transport behavior and superconducting transition temperature T c of NdFe 1- y Ru y AsO 0.89 F 0.11 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 T c 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.