The sensitivity of magnetoresistive read heads can be increased by usi
ng layered magnetic materials showing the giant magnetoresistance effe
ct, instead of a single magnetic film showing the anisotropic magnetor
esistance effect. For this purpose, exchange-biased spin-valve layered
structures are very suitable. For well-chosen compositions and nanome
ter-scale layer thicknesses these materials combine a fair giant magne
toresistance effect with a very small field interval in which the resi
stance change takes place. In this paper we give an overview of aspect
s which determine the functioning of materials of this class in read h
eads, including their preparation, magnetotransport properties and the
magnetic interactions which determine the magnetization reversal proc
ess.