Giant magnetoresistance in magnetic granular systems

Abstract Using a simple model of concentrically coated magnetic granules embedded in a nonmagnetic matrix, we analytically investigated properties in systems of ellipsoidal magnetic granules. It is shown that giant magnetoresistance (GMR) as well as the resistivities of these systems depend strongly on the size and shape of the granules. In particular, there is always an optimum grain size for the magnetoresistance.