Interface, volume, and thermal attenuation of hot-electron spins in Ni80Fe20 and Co.

The relative importance of interface, volume, and thermal scattering in spin-dependent hot-electron transmission of magnetic trilayers is quantified. While interfaces produce significant attenuation (factor 2.2 per interface), the spin asymmetry is dominated by volume scattering. Extracted thermal attenuation lengths (130 A at 300 K for Ni80Fe20) show that thermal spin-wave scattering is stronger than hitherto assumed. This suggests that spontaneous spin-wave emission, rather than the details of the spin-dependent band structure, may cause the strong filtering of minority hot-electron spins.