Giant magnetoresistance in Co1−xCux/Cu multilayers: A new approach to reduced magnetoresistive hysteresis

Co 1−x Cu x / Cu multilayers have been made by sputtering using codeposition of Co and Cu to obtain Co1−xCux alloy layers that are separated by 20 Å Cu spacers. As with Co/Cu multilayers, this Cu spacer thickness corresponds to the second antiferromagnetic maximum. At ambient temperatures, the Co1−xCux/Cu multilayers with x≈0.5 exhibit an absence of magnetoresistive hysteresis resembling that reported previously for Co/Cu multilayers at the second antiferromagnetic maximum when the Co layers are very thin (∼3 Å). The multilayers with Co1−xCux alloys differ significantly from the low-hysteresis Co/Cu multilayers by exhibiting low hysteresis over a larger range of ferromagnetic layer thickness. This is practically significant because it reduces the demands for thickness control during manufacturing.