The magnetization reversal mechanism in an array of submicron elliptical Permalloy elements with an aspect ratio 1.4:1 is investigated using the diffracted magneto-optic Kerr effect technique, Lorentz scanning transmission electron microscopy, and Lorentz transmission electron microscopy. The experimental results are interpreted from a comparison with micromagnetic simulations. The reversal mechanism is found to be dependent on the direction of the magnetic field and to occur via the formation of one or two vortices; the one vortex state is nucleated when the field is applied along the short axis. For the field applied along the long axis a mixture of one- and two-vortex states is observed at remanence.

• Received 5 December 2003

DOI:https://doi.org/10.1103/PhysRevB.69.214404