Superconductor-ferromagnet tunneling measurements indicate sp-spin and d-spin currents

Abstract

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.