Spintronics: Magnetism and Spin-Dependent Transport on the Nanometer Scale

Since the discovery of interlayer exchange coupling and giant magnetoresistance (GMR) in the 1980's spin-dependent transport in magnetic multilayer and nanostructures has attracted a lot of interest. The research was motivated by applications – i.e. GMR read-heads in computer harddisks and the magnetic random access memory (MRAM) – as well as exciting new phenomena, which nowadays constitute the research field called spintronics. The field rapidly developed from investigating magnetic multilayers with layer thicknesses in the nanometer range to a true nanotechnology, which explores magnetism and spin-dependent transport on a nanometer scale. Typical devices are sub-micron sized in all three space dimensions. The recognition of spintronics as a pioneering field for future nanoelectronics culminated in the award of the Nobel Prize in Physics 2007 for the discovery of the GMR effect. Interlayer exchange coupling, giant and tunneling magnetoresistance (GMR, TMR), and current-induced magnetization dynamics as the major novel phenomena of spintronics are reviewed. For each of them a comprehensible physical picture is introduced and discussed.