  The effect of spin-disorder scattering on perpendicular transport in a
magnetic monolayer is considered within the single-site Coherent Potential
Approximation (CPA). The exchange interaction between a conduction electron and
localized moment of the magnetic ion is treated with the use of the $s-f$
model. Electron-spin polarization is evaluated in the tunnel current which
comes from the different densities of spin-up, spin-down conduction electrons
at the Fermi level in a ferromagnetic semiconductor (EuS). Calculated results
are compared with some tunneling experiments.
