THEORY OF MAGNETIC MULTILAYERS - EXCHANGE INTERACTIONS AND TRANSPORT-PROPERTIES

The temperature dependence of the local magnetization in the spin-wave regime is discussed and it is shown that it can be used as a sensitive probe of local exchange interactions in magnetic surfaces and overlayers. The present status of the theory of oscillatory exchange interactions through transition and noble metal spacer layers is reviewed. The theory of the giant magnetoresistance observed recently in some antiferromagnetically coupled multilayers is also discussed. It is shown that both the oscillatory exchange and giant magnetoresistance effects can be understood in terms of different distributions of up and down spin d holes in different parts of the layer structure. The total energy and hence the exchange coupling is determined directly by the d band owing to its high density of states and the transport properties more indirectly through the Mott mechanism in which conduction electrons scatter into d band.