Peltier effect in metallic CPP structures

Here, we report Peltier effect in CPP-GMR structures. CPP-Co/Au and CPP-Cr/Au elements of a small junction size are studied. We expect that Cr/Au interface will show Peltier cooling effect on opposite current direction. R-I curves are obtained from 4-terminal AC resistance measurement with a pulsed DC bias current. The direction of the current from the bottom (Co or Cr) to the top (Au) electrode was defined as positive. From the bulk Seebeck coefficients of Co, Au, and CR, the Peltier coefficients of Co/Au and Cr/Au interface are estimated to be 9.8 mV and -6.0 mV at 300 K, respectively. From the R-I curves, the Peltier coefficient for CPP-Co/Au and CPP-Cr/Au are obtained and compared to those of the Co/Au and Cr/Au interface.