Graphene Spintronic Devices

Spin electronic devices hold out tremendous potential for high-density non-volatile memories, reconfigurable electronic devices and possibly solid-state quantum computing elements. Such devices will almost certainly require new materials to overcome some of the major problems currently arresting progress such as low spin injection efficiency. Carbon nanotubes have been shown to offer some possible benefits, but devices are difficult to fabricate. Carbon nanotubes can be thought of as layers of a hypothetical material graphene rolled into hollow cylinders. We have discovered a way of making planar graphene films, which are just a few atomic layers thick but remain metallic, continuous and of remarkably high quality. This new material offers the same possible advantages as carbon nanotubes for spintronic applications such a coherent spin transport and lack of a Schottky barrier at the ferromagnetic-metal/graphene interface. This programme builds on the current graphene work at Manchester to explore the potential of this material in making novel devices to investigate and optimise spin injection effects and hence allow the production of novel elements for potential applications. The programme will also elucidate the suggested proximity effects at graphite-ferromagnetic interfaces. It has been suggested that at such interfaces a ferromagnetic-like state is induced in the graphite layers at the interface. We can look at this effect on one to three layer graphene stacks by looking for increased spin scattering in the graphene for polarised carriers passing along the interface region. We also intend to look at the potential for using spin current torque effects to reverse the magnetisation direction in a nanomagnet, which is an ideal way of switching devices for non-volatile memory applications.