Micromagnetic simulations of Pac-man-like nanomagnets for memory applications

In this work we study magnetic properties of nanomagnets with lateral dimensions 50-100 nm. These structures have a potential of producing static memories with high storage densities. If simple disk is used as basic nanomagnet, its chirality and polarity cannot be read/write easily by in-plane magnetic field. Based on micromagnetic calculations, we have designed "Pac-man-like" (PL) nanomagnet and calculated its magnetic properties using the oommf code. It solves the micromagnetic problem using the Landau-Lifshitz-Gilbert equation. The calculations have shown, that in the PL shape both, the chirality and the polarity, can be controlled by the in-plane magnetic field with x, y components. The PL shape opens straight channel for the energy relaxation towards stable vortex state with defined chirality and polarity for thickness 32-48 nm, and diameter 50-78 nm.