Study of Dipolar Neighbor Interaction on Magnetization States of Nano-Magnetic Disks

We investigate the effect of magnetic neighbor interaction on the state behavior of nano-magnetic disks for data storage and computation applications. We have observed and verified that a nano-magnetic disk, with certain dimension, can exist either in the single domain state or in the vortex state depending on the edge-to-edge spacing between the nano-magnetic disks. The experiments were conducted by varying the diameters and thicknesses with respect to edge-to-edge spacing. The dimensions were based on the phase diagram between the single domain state and the vortex state. We have observed nano-magnetic disks spaced far apart from its neighbor, settled in the vortex state and coupled nano-magnetic disks with less spacing settled in the single domain state. This phenomenon was observed for nano-magnetic disks with thickness between 8 nm to 20 nm and diameters between 80 nm to 140 nm. We validated the simulation by fabricating pairs of nano-magnetic disks with a thickness of 10 nm and diameter of 110 nm along edge-to-edge spacing from 20 nm to 260 nm in steps of 20 nm.