Using susceptibility and surface resistance measurements of Ba2GdRuO6 and of Ba2GdRu1−uCuuO6, we find that Gd, Ru, and Cu order antiferromagnetically at ∼12.5K, ∼48K, and ∼86K, respectively. The Gd electron spin resonance is exchange-narrowed by paramagnetic Ru, and is broadened to near-undetectability below TN(Ru)=48K. Ru fails lto resonate at all. Antiferromagnetic Cu exhibits a microwave frequency resonance at low fields.
Physica C: Superconductivity and its Applications 341-348(PART 1), pp.571-572