Magnetic multilayers

We discuss some of the fundamental properties unique to magnetic multilayers. Due to a simple competition between exchange and Zeeman energies, complex, spatially nonuniform spin configurations are found to exist. Both bulk and surface phase transitions are discussed. We also consider spin waves in magnetic multilayers with particular attention to canted spin configurations. Spin wave excitations provide a powerful method for studying exchange interactions and spin configurations. Here effective medium calculations are compared to microscopic calculations which need no approximations. Finally, the phenomenon of giant magnetoresistance in magnetic multilayers, where the resistivity of the metallic structure can be changed by over 60% at room temperature, is discussed. A Boltzmann equation approach which involves both bulk and interface spin-dependent scattering is used to understand and predict the transport properties of the multilayer systems, and comparisons between theory and experiment are stressed