Speaker
Description
A program of quantitative measurements of the expulsion of magnetic flux from flat macroscopic samples has been used to categorise expulsion efficiency, and to assess the practical expulsion effects of closed-topological cooling on thin film structures. Specifically, the closed-topology cooling has permitted systematic and repeatable measurements of the magnetic response over the superconducting transition for bulk, thin film and multilayer samples. Particular interest is the magnetic response of superconductor-insulator-superconductor (SIS) multi- layer structures that exhibit a magnetic response that is both enhanced and characteristically different to that of bulk niobium. For SIS multilayer samples under closed topology cooling, we observe a response that we term “flux ratcheting”.
