  No systematic studies have been carried out on the giant magnetoresistance
(GMR) of electrodeposited (ED) Fe-Co/Cu multilayers since the elaboration of a
method for the optimization of the Cu layer deposition potential. In this
paper, we present results on the electrochemical optimization of the Cu layer
deposition potential which was found to depend on the relative iron
concentration in the bath. An X-ray diffraction study of ED Fe5Co95(1.5
nm)/Cu(dCu) multilayers with dCu ranging from 0.8 nm to 10 nm revealed an fcc
structure. For most of the multilayers, a weak superlattice satellite
reflection could be identified. The room-temperature magnetoresistance was
studied in detail as a function of the individual layer thicknesses.
Multilayers with Cu layer thicknesses above about 1.5 nm were found to exhibit
a GMR behavior with a maximum GMR of about 5 % and a typical saturation field
of 1 kOe. The GMR magnitude decreased with increasing Fe-content in the
magnetic layer. The spacer layer thickness evolution of the MR data was
established in detail after separating the ferromagnetic and superparamagnetic
GMR contributions and no oscillatory GMR was found. A comparison with
literature data on both physically deposited and ED Fe-Co/Cu multilayers is
also made.
