Perpendicular giant magnetoresistance of electrodeposited Co/Cu-multilayered nanowires in porous alumina templates

The giant magnetoresistance GMR of multilayered Co/Cu nanowires potentiostatically electrodeposited inside the pores of an anodized alumina template was studied in the current perpendicular to the plane CPP geometry. The maximum magnetoresistance change of 13.5% was observed for Co 8 nm /Cu 10 nm nanowires at room temperature. The interfacial roughness and/ or an intermixing between Co and Cu layers were varied by changing the Cu deposition potential. However, the CPP-GMR value only slightly decreases as the Cu deposition potential increases to the positive value. This indicates that the interfacial roughness and/or intermixing are not a crucial factor in determining the CPP-GMR value of the Co/Cu nanowires, which is argued to be due to the uncoupled magnetic layers. The x-ray diffraction shows that Co/Cu nanowires with 300 nm diameter have a face-centered-cubic structure with a strong 111 texture along the wire axes; their magnetic easy axes are perpendicular to the wire axes as determined from the CPP-GMR curve. The effects of the interface roughness and/or an intermixing between Co and Cu layers and their thickness variation on the CPP-GMR are discussed. © 2006 American Institute of Physics. DOI: 10.1063/1.2168290