Magnetic ordering in the superconducting mixed ruthenium-copper oxide Sr2Y(Ru1-xCux)O-6

A series of mixed ruthenium-copper oxides of general formulae Sr2Y(Ru1-xCux )O-6 x=0.05, 0.10, 0.15 were prepared by high temperature synthesis. Transp ort and specific heat measurements at low temperatures showed these materia ls to be superconducting with T-C of approximately 24K and to have magnetic transitions. High-resolution neutron powder studies have been undertaken t o determine the crystallographic structure and magnetic ordering present in the samples. The materials were found to he single phase P2(1)/n with a=5. 7602 Angstrom, b=5.7795 Angstrom, c=8.1506 Angstrom and 90.313 degrees for x=0.05 samples. The structure is related to that of the parent compound wit h additional ruthenium-copper ordering. In addition to the structural peaks , antiferromagnetic peaks were observed at temperatures below 28K confirmin g the magnetic order.