  We investigate the influence of the exchange field on the Andreev bound
states in a ferromagnetic (F) film backed on one side by a superconductor (S).
Our model accounts for diffusive reflection at the outer surface and possible
backscattering at the FS-interface. Phase shifting of the Andreev level by the
exchange field results in an oscillatory behaviour of the density of states of
F as a function of the layer thickness. We show that our results agree
quantitatively with recent experiments.
