Supercurrent transmission through Ni/Ru/Ni synthetic antiferromagnets.

Josephson junctions containing ferromagnetic materials are generating interest for use in superconducting electronics and cryogenic memory. Optimizing the performance of such junctions is an ongoing effort, requiring exploration of a broad range of magnetic systems. Here we study supercurrent transmission through Ni/Ru/Ni synthetic antiferromagnets, with the idea that their magnetic properties may be superior to those of isolated Ni layers. We find that the decay of the supercurrent as a function of Ni thickness is very slow, with a decay length of 7.5 $\pm$ 0.8 nm. We also characterize the magnetic properties of the synthetic antiferromagnets as a function of Ni and Ru thicknesses.