Superconductor-ferromagnet tunneling measurements indicatesp-spin andd-spin currents

Spin polarization of tunneling electrons was observed to decrease as the barrier thickness decreased. The polarization measured by the Meservey-Tedrow technique has been separated into a positively and a negatively spin polarized current arising from $sp$- and $d$-like interfacial states. The model for separating $sp$- and $d$-like spin currents is expressed with an interface transmission probability, a decay rate within the barrier and polarization for each of the channels. The present observation can also have an impact on the downscaling of TMR elements.