Observation of magnetization reversal process in Ni-Fe nanowire using magnetic field sweeping-magnetic force microscopy

The details of the magnetization reversal process of Ni-Fe nanowires, which were 10, 30, and 50-nm thick, were successfully observed using our newly proposed magnetization measurement method, namely, magnetic field sweeping (MFS)-magnetic force microscopy (MFM). All the points within the nanowire show marked phase changes (stray fields change) as the magnetic field is varied. In particular, each nanowire edge displays a hysteresis loop, while the center shows a sharp jump or a plateau area. These results demonstrate that domain wall motion is dominant in the magnetization reversal process of a 10-nm-thick Ni-Fe nanowire and that domain wall motion along with domain wall pinning play important roles in the magnetization reversal process in both 30- and 50-nm-thick Ni-Fe nanowires.