  The dependence of the critical current density j_c on the ferromagnetic
interlayer thickness d_F was determined for Nb/Al_2O_3/Cu/Ni/Nb Josephson
tunnel junctions with ferromagnetic \Ni interlayer from very thin film
thicknesses (\sim 1 nm) upwards and classified into F-layer thickness regimes
showing a dead magnetic layer, exchange, exchange + anisotropy and total
suppression of j_c. The Josephson coupling changes from 0 to pi as function of
d_F, and -very close to the crossover thickness- as function of temperature.
The strong suppression of the supercurrent in comparison to non-magnetic
\Nb/Al_2O_3/Cu/Nb junctions indicated that the insertion of a F-layer leads to
additional interface scattering. The transport inside the dead magnetic layer
was in dirty limit. For the magnetically active regime fitting with both the
clean and the dirty limit theory were carried out, indicating dirty limit
condition, too. The results were discussed in the framework of literature
