Peltier Effect in Sub-micron-Size Metallic Junctions

Resistance ( R )–current ( I ) curves in trilayer CPP-GMR (current perpendicular to plane-giant magnetoresistance) elements show a parabolic baseline because of Joule heating, and abrupt jumps due to magnetization reversals. The bottom of the parabolic baseline shifts in one current direction for reasons that were previously unclear. Our study of the R – I characteristics of CPP elements with various structures showed (i) the shift in the R – I curve originates from Peltier cooling in the CPP elements; (ii) the cooling power per unit area of the CPP elements (∼10 5 W/cm 2 ) is much greater than that of conventional thermoelectric materials (∼5 W/cm 2 ).