Supercurrent in ferromagnetic Josephson junctions with heavy metal interlayers*

For exploring superconductor-ferromagnet proximity effects, Josephson junctions typically take the form: S/N/F/N/S, where S denotes a superconductor, F a ferromagnet and N a normal metal. The role of the N spacer layer is usually to promote the growth of the F layer – which may not be well lattice matched with the S layer. The critical current density of these junctions diminishes over very small thicknesses of F due to the exchange field dephasing the Cooper pairs. By including two additional F’, F” layers in a S/N/F’/N/F/N/F”/N/S junction, singlet Cooper pairs can be converted to spin aligned triplet Cooper pairs, which are not dephased by the exchange field and penetrate deep into the middle F layer. It has been theoretically predicted that replacing the N/F’/N and N/F”/N layers with a single layer N_SOC (where N_SOC is a heavy metal with Rashba spin orbit coupling) can also generate triplet Cooper pairs. In this work we describe our experimental progress to realize such a junction.