Detection of the static and kinetic pinning of domain walls in ferromagnetic nanowires

Two distinct pinning mechanisms named as kinetic and static pinning of magnetic domain wall (DW) are experimentally resolved. Both the pinning situations are realized at an artificial notch on U-shaped Permalloy nanowires, depending on the initial DW states, moving or pinned. The kinetic depinning field-a critical field for a moving DW to be trapped at a notch-is revealed to be distinguishably smaller than the static depinning field-a critical field to depin a trapped DW at the notch. Based on one-dimensional collective model, the discrepancy is explained by the tilting angle of the moving DW. (C) 2009 American Institute of Physics. [doi:10.1063/1.3248220]