Magnetic and magnetotransport properties in metastable granular systems

A negative, isotropic magnetoresistance (MR) has been measured in a wide class of nanogranular magnetic materials produced by off-equilibrium techniques. The common feature of these magnetic systems is the granularity, either structural or magnetic, on the nanometer scale. In this work analogies and differences among magnetotransport effects observed in bi-metallic alloys, either in bulk or thin-film form, will be highlighted. In addition, the role and nature of interparticle interaction on magnetic and magnetotransport properties of nanogranular systems will be discussed.