Microelectronic devices are evolving to include a wide range of non-traditional materials which provide functionality not available in the standard semiconductor materials set. In particular, incorporation of magnetic materials allows a range of new magnetoelectronic devices to be built, for example magnetic random access memories and magnetoresistive readback heads. This project explores materials issues in mesoscopic multilayer rings, with a view to their incorporation in future magnetoelectronic devices. Thin-film multilayer rings will be used as a test bed for studying magnetic behavior. Rings are ideal for several reasons: they can be magnetized to have a range of domain wall geometries, or no walls; they do not have end domains as seen in elongated thin film structures; and they have a variety of possible magnetization states which could be suitable for storage of multiple bits in a memory device. Rings of different geometries, microstructures and layer sequences will be made, and their magnetization states, static behavior and dynamic behavior will be investigated using magnetooptical measurements, light scattering, and magnetoresistance measurements, and related to composition and layer sequence, microstructure and processing. This is a collaborative project between researchers in MIT and Prof. Bland and collaborators in Cambridge University, UK. The broader impacts of the work include training, joint educational activities such as distance learning, and development of demonstration materials for high school teaching, taking full advantage of the international nature of the collaboration.
