Impact of Scaling on the Dipolar Coupling in Magnet–Insulator–Magnet Structures

The ability to control the magnetization of individual nanomagnets has made possible a broad class of devices, which store and manipulate information in the form of magnetization. For these devices to serve as building blocks for computation, they must be concatenable while allowing the information to flow in a directional manner. One scheme that has been proposed for this is the use of a dipolar coupling unit, a vertical stack of magnet–insulator–magnet, in which the information is transmitted from one magnet to the other through dipolar interaction. In this paper, we have used a novel magnetic force microscopy-based approach to demonstrate that a vertical dipolar coupling unit can be used to transfer information. We also investigated how the strength of the interaction can be maximized while preserving the directionality. The experimental observations were understood using micromagnetic simulations, and a scaling approach has been proposed for ultra-thin magnets.