  We report electrical measurements showing the degradation processes of
LaMnO$_{3-y}$ (LaMnO) in LaMnO/normal metal interface in both point contact and
planar-type junctions. Immediately after the preparation of the interface, the
degradation process was followed by measuring the evolution of the junction
resistance versus time. This process is characterized by the appearance of a
second maximum in the resistance vs. temperature (R-T) dependence at
temperatures lower than the Curie temperature T$_c$, at which the
metal-insulator transition occurs in the bulk. These effects are explained in
terms of the formation of a depleted interface layer in LaMnO caused by an
out-diffusion of oxygen from the manganite surface to the normal metal. This
assumption is confirmed by XPS measurement. Similar results on LaSrMnO$_{3-y}$
interfaces are also obtained.
