Observation of the Conduction Electron Spin Polarization in the Ag Spacer of a Fe=Ag=Fe Trilayer

The spatially oscillating electron spin polarization in the Ag spacer of a 4n m Fe=20 nm Ag= 4n m Fe001 epitaxial trilayer has been determined by means of low energy muon spin rotation. It oscillates with the same period as the interlayer exchange coupling, but shows a much weaker attenuation at large distances x from the interface. The measured magnetization profile from the inner 14 nm of the spacer is described by an oscillating polarization decaying as x 0:81 . This unusual behavior may arise from a full confinement of electron states within the spacer.