Thermo-electric effect in a nano-sized crossed Permalloy/Cu junction under high bias current

Abstract

We show that the difference in the Seebeck coefficients between two voltage probes produces an additional electric signal in the local resistance measurement of the submicron-sized junction. This is because the temperature increase at the junction induced by the Joule heating produces unnegligible Seebeck voltage in addition to the Ohmic voltage. In nanostructured systems, since the temperature variation becomes quite high under the high-bias current, the Seebeck voltage dominates the detected electrical voltage. This provides a consistent description for unusual bias-current dependences of the differential resistance in nano-sized metallic junction systems.