Polarized-neutron scattering study of the Cooper-pair moment in Sr2RuO4

We report a study of the magnetization density in the mixed state of the unconventional superconductor Sr2RUO4. On entering the superconducting state we find no change in the magnitude or distribution of the induced moment for a magnetic field of 1 T applied within the RuO2 planes. Our results are consistent with a spin-triplet Cooper pairing with spins, lying in the basal plane. This is in contrast with similar experiments performed on conventional and high-T-c superconductors.