THE GIANT MAGNETORESISTANCE AND MAGNETIZATION OF SPUTTER-DEPOSITED COCU MULTILAYERS/

We have prepared (111) Co/Cu multilayers using d.c. magnetron sputteri ng which exhibit room temperature giant magnetoresistances (GMR) aroun d 65%. These values are similar to the record for this system, but mor e than 20% higher than those reported by other workers. Such big diffe rences are not fully explained, and have been attributed to difficulti es in finding the optimum growth conditions. Here we present results o n the effect of annealing one of these very high GMR multilayers. The aims of this study were to relate changes in the multilayer structure to the magnetic properties of the sample and the GMR. By using X-ray c haracterisation and vibrating sample magnetometer measurements we have found that large changes in the GMR are associated with a reduction i n the volume fraction of antiferromagnetic alignment, while there was very little (if any) change in the quality of the layering.