Quantitative analysis of magnetization reversal in submicron S-patterned structures with narrow constrictions by magnetic force microscopy

We present a quantitative study of magnetization reversal and domain wall pinning phenomenon in an S-patterned ferromagnetic wire with narrow constrictions by magnetic force microscopy (MFM). The variation of domain structures with magnetic field is evidenced by electron transport measurements, simulation, and MFM images. The switching behaviors are strongly affected by narrow constrictions connecting the half-ring wires. The proposed MFM analysis effectively separate the local hysteresis loops at the arc section and the narrow constriction, which provide quantitative data, including relative magnetization intensity, local switching field, and domain wall depinning field for the multidomain wire. The MFM results correlate with other experimental data well, and provide direct evidence that the domain state at constriction dominates the magnetoresistance behavior. (C) 2005 American Institute of Physics.