Evidence of high dissipation in magnetization reversal processes of five Co/Cu bilayers

Heat and charge transport perpendicular to the plane in five Co/Cu stacks are studied using AC temperature gradients in the presence of a DC current. Large peaks in AC voltage response versus applied field are observed. This effect, measured only in reversible magnetization reversal modes and at sharp values of magnetic fields, suggests that an extra dissipation process is produced at well-defined magnetic configurations.