Nonreciprocity is the key to many signal processing devices such as isolators and filters. In magnetic thin films, one can find this nonreciprocity as a result of surface-induced symmetry breaking. We were motivated by the idea that if the magnetic exchange interaction is nonuniform through a material, then nonreciprocity may be tunable. In this theoretical work, we found that there are special frequencies and excitation-lengths at which signals will propagate left, but not right, and vice versa. These frequencies can occur in both the GHz or THz range, making them of potential use in microwave and far-infrared device.About the presenter
Dr Karen Livesey is a theoretical condensed matter physicist based at the University of Newcastle and is a Scientific Associate Investigator in FLEET. Her research interests are in (i) exotic behaviours in magnetic thin films, and (ii) magnetic nanoparticles for biomedical applications. It is the first research area (magnetic thin films) that overlaps with the research themes within FLEET. Her current work is focussed on analytically calculating the size and shape of domain walls and skyrmions in order to provide scientists and engineers with simple tools with which to analyse experiments and design materials for important device application.