Magnetic and transport properties of sub-micron ferromagnetic wires

Submicron Co wires with a variable width in the range from 0.2 to 2 /spl mu/m and paired Co disks with a variable diameter in the range from 0.4 to 5 /spl mu/m were prepared to investigate the magnetoresistance effect in association with the domain wall formation. A clear change in resistivity due to traversing domain wall along the wire is observed for all the widths in both longitudinal and transverse magnetoresistance effects. The domain wall gives a negative contribution to the magnetoresistance effect. Longitudinal magnetoresistance effects of paired Co disks show an anomalous increase in low fields below 20 kOe due to the peculiar vortex structure stabilized in the disk.