MAGNETORESISTANCE IN GRANULAR METALLIC SYSTEMS

The magnetic and transport properties of ferromagnetic clusters embedd ed in a metallic host are studied. A simple model is presented to expl ain the observed behaviour of the magnetoresistance in such systems. T he role played by both the dipolar interaction between the clusters an d the ratio of the electronic mean free path in the non-magnetic mater ial to the average inter-cluster distance is clarified. Finally, a sug gestion is made of systems in which the best magnetoresistance ratios are expected to be found.