Spin depolarization in Ni and Ce

Spin polarized electrons produced by polarized light in a Ge single crystal are depolarized by thin layers of Ni and Ce deposited on the surface of the sample. The mean free path for spin-exchange scattering is found to be (12.5 ± 1.5) Å in Ni and (3.2 ± 1) Å in Ce. The depolarization by Ce is found to be identical at 300 and 4 K. It is concluded that the occupancy of the 4? shell of the Ce atoms is similar at both temperatures.