  A fabrication process for vertical organic spin-valve devices has been
developed which offers the possibility to achieve active device areas of less
than 500x500 nm^2 and is flexible in terms of material choice for the active
layers. Characterization of the resulting devices shows a large
magnetoresistance of sometimes more than 100%, however with equally large
variation from device to device. Comparison with large-area spin-valves
indicates that the magnetoresistance of both, large and small devices most
likely originates from tunneling through pinholes and tunneling
magnetoresistance.
