Co-Cu heterogeneous alloy nanowires with diameters down to 20nm and lengths
of several tens of mu m have been prepared by constant current electrodepo
sition in anodic aluminium oxide membranes. As-deposited nanowires exhibit
room temperature giant magnetoresistance (GMR) of less than 1%, but this in
creases significantly on annealing. The shape of the GMR curves depends str
ongly on whether the applied field is parallel or perpendicular to the nano
wire axis.