Magnetoresistance behavior of nanoscale antidot arrays

We investigate the transport properties of nanometer-scale Ni₈₀Fe₂₀ antidot arrays fabricated using deep ultraviolet lithography. Magnetotransport measurements have been shown as a powerful and sensitive technique in mapping the magnetization reversal process in complex magnetic structures. Compared with continuous film, a drastic increase in coercivity in the antidot structures due to local modification of the spin configurations was observed. We found that the current density distribution is periodically modulated by the presence of holes, which gives rise to the interesting high-field sloping behavior of the magnetoresistance (MR). The effect of antidot film thickness for fixed lateral geometry on the MR response was also investigated, and the reversal process was found to be strongly dependent on the antidot film thickness. Our experimental results were further verified by magnetic hysteresis measurements and micromagnetic simulations, which show good agreement with the experimental MR data.