Triplet proximity effects and electrical transport of spin-orbit coupled superconductor/ferromagnet hybrids

<p dir="ltr">This dissertation reports a detailed study of the fabrication and characterisation of Nb based spin-orbit coupled superconducting spin valves, with further application to superconducting diodes using the same structure. Recently, spin-orbit coupling was used to simplify the structure required to generate triplet Cooper pairs in Nb/Pt/Co/Pt, with the triplet/singlet conversion rate and thus critical temperature being controlled via the magnetisation of the Co layer. In this work we present significantly enhanced pair conversion in this structure due to interfacial engineering. Depositing subnanometer layers of metallic and oxide dusting has allowed for enhanced control over the proximity effect in such devices that wasn’t previously found. Cu and Au both enhanced the triplet proximity effect, with Au having a greater impact due to the added benefit of contributing to spin-orbit coupling. MgO dusting resulted in a significant enhancement of critical temperature suppression in both magnetic orientations which went against the understanding of previous work indicating more work needs to be completed. Fabrication of Hall bars formed of spin-orbit coupled superconducting spin valves successfully produced the superconducting diode effect with up to a 70% efficiency with an IP applied field. We suggest that the strong Rashba SOC with the IP magnetic field is causing Cooper pairs to gain finite momentum which leads to a non-reciprocity of the critical current. A temperature and current channel width dependence study was also completed which demonstrated that a 4.4 μm channel and 4.5 K was optimal for diode efficiency.</p>