Angular Magnetoresistance of Nanowires with Alternating Cobalt and Nickel Segments

Magnetization reversal in segmented Co/Ni nanowires with varying number of segments was studied using angular magnetoresistance (MR) measurements on isolated nanowires. The MR measurements offer an insight into the pinning of domain walls (DWs) within the nanowires. Angular MR measurements were performed on nanowires with two and multiple segments by varying the angle between the applied magnetic field and nanowire (-90° ≤ θ ≤ 90°). The angular MR measurements reveal that at lower values of θ, the switching fields are nearly identical for the multisegmented and two-segmented nanowires, whereas at higher values of θ, a decrease in the switching field is observed in the case of two-segmented nanowires. The two-segmented nanowires generally exhibit a single DW pinning event, whereas an increased number of pinning events are characteristic of the multisegmented nanowires at higher values of θ. In situ magnetic force microscopy substantiates reversal by DW nucleation and propagation in multisegmented nanowires.