Micromagnetic simulation of non uniform nanodots with perpendicular anisotropy

Multilayered Pt/[Co/Pt]/sub 5/ films were fabricated into patterned dots with diameters of 120 and 200 nm by laser interference lithography. Anomalous Hall effect (AHE) measurements were used on an array of dots to measure the switching field and the effects of reversal of an area with reduced anisotropy in the dot were also investigated by micromagnetic simulation. It was shown that a reduction in switching field is caused by an area of reduced anisotropy. The effect of various combinations of a reduction in anisotropy and/or exchange constant, and the size and shape of the area were also discussed in this paper.