Magneto-transport in ferromagnetic granular networks

Using numerical simulations and analytical calculations we have examined the transport properties of a ferromagnetic granular systems. We model this complex network system by an ensemble of ferromagnetic conducting grains randomly located on a 2D plain. Quite surprisingly, the magneto-resistance of a complex network can be approximated by the magneto-resistance of a single pair of ferromagnetic grains, although our simulations show that the transport trajectories change from a quasi-1D path through the system to a percolation network through the larger grains as the number of grain in the system increases.