MAGNETIC MULTILAYERS - SPIN CONFIGURATIONS, EXCITATIONS AND GIANT MAGNETORESISTANCE

We discuss some of the fundamental properties unique to magnetic multi layers. Complex spin configurations are examined for many different sy stems and are shown to arise from a simple competition between exchang e and Zeeman energies. The spin configurations found in multilayer sys tems determine macroscopic properties such as the static susceptibilit y and magnetization, and can lead to anomalous field and temperature b ehaviour. We also discuss the dynamic behaviour of magnetic multilayer s. Emphasis is placed on spin waves in magnetic multilayers with cante d spin configurations and the softening of modes at magnetic phase tra nsitions. Furthermore we show that spin wave excitations provide a pow erful method for studying exchange interactions and spin configuration s. Finally, the phenomenon of giant magnetoresistance in magnetic mult ilayers, where the resistivity of the metallic structure can be change d by over 60% at room temperature, is discussed. Simple theoretical ap proaches are used to understand and predict the properties of the mult ilayer systems and comparisons between theory and experiment are stres sed.