Effect of Granule Shape on the Giant Magnetoresistance for Ferromagnetic Metal-Metal Granular Films

In order to investigate the effect of granule shape on the giant magnetoresistance, assuming that granular films consist of ellipsoidal ferromagnetic granules embedded in a nonmagnetic metal matrix and the ellipsoidal granules have different demagnetizing factors in three directions, we combined two-current model with the effective medium theory to investigate the effect of granule shape on the giant magnetoresistance. The results revealed that the giant magnetoresistance in granular films depended strongly on the granule shape and was between those for current perpendicular to the plane of the layers and current in the plane of the layers in magnetic multilayers.