Vortex chirality control in circular disks using dipole-coupled nanomagnets

We report a systematic control of the chirality of circular magnetic disks where dipole field coupling drives the functionality. Our approach involves the use of two rhomboid nanomagnets with predetermined magnetization directions to bias the circular disk. Magnetostatic interaction was observed to initiate the vortex nucleation with selective chirality (clockwise or counterclockwise) when an appropriate in-plane magnetic field was applied and then removed. We have used in-field magnetic force microscopy technique to directly probe the direction of the vortex core displacements, which are sensitive to its chirality. Experimental results are in good agreement with micromagnetic simulations. (C) 2015 AIP Publishing LLC.