Multivortex Formation During Magnetization Reversal Process in Rectangular and Square CoFe Nanostructures

Abstract

Shape- and thickness-dependent magnetization reversal process is investigated in CoFe nanostructures by micromagnetic simulations. The reversal is abrupt in the case of 10-nm and 20-nm thick rectangular and square nanostructures. Intermediate double vortex states are formed in rectangular nanostructures of thickness 30 to 60 nm when the field is applied along the longer dimension. Magnetization reversal along the shorter dimension happens through the formation of multivortex states. Similar type of reversal is observed in 40 to 60-nm thick square nanostructures of dimensions 225 nm and 335 nm.