  We measured the critical current of the bilayer Nb/Co in the applied magnetic
field. When the magnetic field was tilted to the axis which was perpendicular
to the plane of the bilayer we observed a large difference in critical currents
flowing in opposite directions. We found that the largest critical current of
the bilayer exceeded the critical current of the superconductor without Co
layer in a wide range of the tilted magnetic fields. The theory which takes
into account the surface barrier effect for vortex entry and magnetic field of
the magnetic layer gave a quantitative explanation of our experimental results.
