Dependence of field driven domain wall velocity on cross-sectional area in Ni65Fe20Co15 nanowires

The velocity of vortex domain walls (DWs) was measured versus magnetic field in Ni65Fe20Co15 nanowires with different widths and thicknesses using time-resolved anisotropic magnetoresistance measurements. The Walker breakdown field, which separates translational and precessional DW propagation regimes, decreases for wider and thicker nanowires. On the contrary, the peak velocity at the Walker breakdown field is independent of the nanowire width and thickness. The Gilbert damping parameter α was measured independently and was found to be insensitive to nanowire width but decreased with increasing wire thickness. From these data the transverse anisotropy field and dynamical DW width could be determined.