CPP charge and heat transports in multilayered nanowires the spin-Peltier effect

We investigate here, beyond conventional giant magnetoresistance (GMR) and magneto-thermoelectrical power (MTEP) measurements, Co/Cu multilayer nanowires in a true current-perpendicular-to-the-plane (CPP) geometry by a novel magnetothermogalvanic voltage (MTGV) experiment. It measures the thermopower under an AC heat current through a nanowire experiencing a DC charge current. Our data exhibit a magnetic response of the MTGV about twice as much as GMR and MTEP. We account for this effect through a model that treat the heat and charge transports in a generalized two-current model. It arises a Peltier-like effect that adds to the effective electrical resistance. This term accounts for carrier entropy and is highly sensitive to magnetic configurations of multilayered nanostructures. Thus MTGV is an out-of-equilibrium measurement that probes the local Peltier effects that occur at each location where there is a magnetic inhomogeneity.