Conventional electronics utilises only the charge of the electron: Spintronics additionally uses the intrinsic 'spin' of the electron as a further state variable to process, convey, and store information. Novel spintronic device architectures promise both enhanced capabilities and reduced power consumption: one outcome of this so-far is the massive increase in magnetic data-storage capacity in recent years, which has enabled high data-capacity consumer technologies such as personal media players, internet email and data storage, and high-definition television-on-demand services. My research centres around the fundamental physical mechanisms underpinning spin-polarized electrical conduction and magnetism in nanostructured spintronic devices. This is achieved using a combination of magnetic and electrical measurements, in conjunction with synchrotron x-ray and neutron scattering techniques.
Spin-polarised currents naturally arise in ferromagnetic metals. However, the effects which are useful in harnessing such currents for spintronics - spin-coherence, electrostatic screening, and evanescent decay lengths; electron mean-free-paths; magnetic domain-wall widths etc. - typically involve lengthscales on the nanometer scale. The passage of spin-polarised currents through a device is intrinsically linked to the detailed electronic structure of materials, making it possible to probe fundamental quantum-mechanical effects in magnetic nanostructures from something as simple as electrical resistance measurements. In order to study and exploit spin-polarised currents it is often necessary to fabricate thin-film or multilayered magnetic devices: magnetic thin-films and nanostructures present a wealth of novel and interesting physics in themselves. One aspect in which I am interested is hybrid structures combining metallic magnetic materials with semiconductors: incorporating the spin degree of freedom in inorganic semiconductor (Si, GaAs etc.) devices allows extension of traditional functionality, whilst organic semiconductors provide the scope for spintronic functionality to be added in future low-cost printable and flexible electronics.