Magnetization switching in alternating nanowires 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 248 nm 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, t40 nm, spin rotation dominates the reversal process. For t40 nm, 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.