Huge enhancement of the magnetoresistance in nanoparticle arrays

We show that the interplay between charging effects and the non-equilibrium spin accumulation has a dramatic effect in the current through an array of nanostructures attached to ferromagnetic electrodes. Large oscillations in the current as a function of bias voltage show up for parallel orientation of the electrodes' magnetizations. These oscillations originate in the inhomogeneity of the spin potentials through the array and correlate with oscillations in the spin accumulation. For antiparallel orientation the spin potential is homogeneous and the oscillations do not show up.This sensitivity results in a huge enhancement of the tunneling magnetoresistance as compared to the single-island case, and open new routes for improving the spintronic response of nanodevices.