Figure 4

Reversal field as a function of Pt thickness. In (a), for different periodic edge-modulated nanowires the reversal field goes up rapidly from 0 nm to 1 nm Pt thickness, for thicker Pt the reversal field is roughly constant. In (b), the normalized reversal field shows that the behaviour as a function of Pt thickness is, indeed, independent of the nanowire geometry. Insert, Scanning electron microscopy (SEM) images of nanowires show the different geometries used to studied DW propagation in NiFe with a Pt overlayer. The triangles, dots and squares observed in (a) and (b) are related to parallel sided and periodic modulated 30 and 75 nm amplitude, respectively.