  Room-temperature transport properties (the zero-field resistivity, \rho 0,
and the GMR) were studied for ED Ni50Co50/Cu multilayers as a function of the
individual layer thicknesses and total multilayer thickness. The Cu deposition
potential was optimized in order to obtain the preset layer thicknesses. The
surface roughness development was studied by AFM, which revealed an exponential
roughening with total thickness. The Cu layer thickness strongly influenced the
roughness evolution. As expected, \rho 0 decreased with increasing Cu layer
thickness whereas it increased strongly for large total multilayer thicknesses
that could be ascribed to the observed deposit roughening. All multilayers with
Cu layer thicknesses above about 1.5 nm exhibited a GMR behavior with a maximum
GMR of about 5 %. The GMR decreased for total multilayer thicknesses above
about 300 nm due to the strong increase of \rho 0, the latter caused by the
enhanced roughness. The GMR data indicated the appearance of a current at angle
to plane type scattering due to the layer undulations. The thickness evolution
of the MR data was analyzed in detail after separating the ferromagnetic and
superparamagnetic GMR contributions. It could be established that ED Ni-Co/Cu
multilayers do not exhibit an oscillatory GMR behavior with spacer thickness.
