Magnetoresistance Effect of Co–Cu Nanostructure Prepared by Electrodeposition Method

It was possible to produce Co–Cu multilayer and alloy films controlled in the atomic scale by electrodeposition. We have examined the magnetoresistance (MR) in the Co–Cu multilayers and the alloy films produced by electrodeposition and have investigated the relationships between the magnetoresistance and film thickness, composition, and magnetization. For the Co–Cu multilayer films the maximum MR ratio at 300 K is about 16% (21 kOe) and at 5 K it increases to about 24%. The MR ratio is more strongly dependent on the Co alloy ferromagnetic layer thickness than the change of the composition near the interface between Co alloy and Cu layers. The giant magnetoresistance has also been observed for Co–Cu alloy films. The maximum MR ratio of the Co–Cu alloy films increases to 6.3% after annealing the film at 723 K for 1 hour.