MAGNETIC MULTILAYERS

We discuss some of the fundamental properties unique to magnetic multi layers. Due to a simple competition between exchange and Zeeman energi es, complex, spatially nonuniform spin configurations are found to exi st. Both bulk and surface phase transitions are discussed. We also con sider spin waves in magnetic multilayers with particular attention to canted spin configurations. Spin wave excitations provide a powerful m ethod for studying exchange interactions and spin configurations. Here effective medium calculations are compared to microscopic calculation s which need no approximations. Finally, the phenomenon of giant magne toresistance in magnetic multilayers, where the resistivity of the met allic structure can be changed by over 60% at room temperature, is dis cussed. A Boltzmann equation approach which involves both bulk and int erface spin-dependent scattering is used to understand and predict the transport properties of the multilayer systems, and comparisons betwe en theory and experiment are stressed.