Magnetism and superconductivity in Sr2YRu1-uCuuO6 and magnetism in Ba2GdRu1-uCuuO6

We report magnetization, surface resistance (R-s(T,H)), and electron spin r esonance (ESR) for non-superconducting Ba2GdRu1-uCuuO6, and find that all t hree magnetic ions (Gd, Ru, and Cu) are ordered at low temperatures. Both E SR (Gd sublattice) and weak ferromagnetic resonance (dopant Cu) are observe d, while no magnetic resonance due to either paramagnetic or ordered Ru is detected; In addition, for superconducting (Te similar to 45 K) Sr2YRu1-uCu uO6, resistivity, muon spin rotation (mu(+)SR), and Ru-99 Mossbauer absorpt ion are reported. None of the O-6 materials (e.g., Sr2YRu1-uCuuO6) have cup rate planes, although Cu is employed as a dopant. In Sr2YRu1-uCuuO6, the Ru moments order at a temperature (similar to 23 K) below that for the resist ive onset of superconductivity, while the Cu orders at a higher temperature , similar to 86 K. Therefore at low temperatures, this material exhibits ma gnetic order, coexisting with diamagnetism. The only non-magnetic layers in the superconducting O-6 structure, the SrO layers, carry holes and exhibit diamagnetic screening characteristic of type-II superconductivity.