Magnetization switching in alternating width nanowire arrays

A systematic investigation of the magnetization reversal mechanism in arrays of Ni₈₀Fe₂₀ nanowires with alternating width is presented. The structures were fabricated using deep ultraviolet lithography followed by lift-off technique at 2480.3em0exnm exposure wavelength. We have mapped the magnetization reversal processes and observed that the switching mechanism is very sensitive to the thickness to width ratio of the nanowires. For wire thickness, t400.3em0exnm, spin rotation dominates the reversal process. For t>400.3em0exnm, however, the reversal process is mediated by the curling mode of reversal. The dipolar field is strongly influenced by the nanowire of larger width in the alternating width array. Our results were compared with homogeneous width nanowire array of similar thicknesses and marked differences were observed.