Comparison of Magnetization and Magnetoresistance in Co/Cu Multilayers

Multilayers of the form [Cu(t)/Co(25 angstrom)](25) have been prepared by dc magnetron sputtering. Magnetization and magnetoresistance measurements have been carried out by applying the magnetic field either parallel or perpendicular to the film plane. Correlation between magnetization and magnetoresistance has been discussed. For in-plane measurements of magnetoresistance, the observed behavior is attributed to the presence of a distribution of grain sizes in the Co layers. Measurements with field perpendicular to the film plane also revealed that magnetoresistance behaviour is due to the distribution of grain size. However, the perpendicular measurements show larger fields to obtain the peaks observed in the magnetoresistance and that the positions of the magnetoresistance peaks are lying well above the magnetic coercivity. These observations indicate that both magnetization reversal and spin dependent scattering at the interfaces play significant roles in the observed magnetoresistance behaviour.