Enhanced Nucleation of Magnetic Vortex in Geometrically Confined Nanodots

Due to its combination of controlled chirality and polarity, the magnetic vortices have attracted increasingly scientific efforts in application as multibit memory cells. Here, we show the modeled vortex-state elements in soft ferromagnetic nanodots with smaller critical dimensions by micromagnetic numerical calculations. By applying in-plane rotating magnetic field of sufficient strength and frequency, the vortices polarity can be switched in a unidirectional way. Compared with conventional disks, the packed noninteracting nanodots assembled by such method possess the advantage of high areal density, which reveals its potential application in nonvolatility random access memory devices.