Magnetism and superconductivity in Sr(2)A(Ru1-xCux)O-6 (A = Y, Ho) system

We have synthesized a series of Cu-doping Sr(2)A(Ru1-xCux)O-6 compounds, wh ere A = Y or Ho. We observed superconducting transition in samples with x > 0.04. In addition, magnetic orders at a temperature close to that of the s uperconducting transition, are present in the samples. There is an addition al magnetic order at about 15 K in Ho samples. Detailed magnetic measuremen ts suggest that this 15 K transition is ferromagnetic in nature, presumably due to Ho order. The observed striking features can be understood in terms of a model based on the double exchange mechanism, which occurs via Ru5+ s pin coupling to itinerant electrons hopping between Ru-site. (C) 2000 Publi shed by Elsevier Science B.V. All rights reserved.