Analysis of the tunnel resistance and magnetoresistance in Co nanoparticles including the cluster size distribution

Abstract We have calculated the electrical resistance as a function of temperature, from a phenomenological model, for a system composed of a layer of spherical Co cluster inside the insulating barrier of a magnetic tunnel junction. For each temperature, the electrical resistance at low voltages was obtained adding the contributions arriving from different grain size channels. A computer routine were used to fit experimental data found in the literature. The large contribution for the electrical conduction emerging from the larger cluster channels suggests that in this system a non-negligible part of the tunnel magnetoresistance is due to grains that are not Coulomb blockade.