Circular permalloy elements were fabricated by a combination of electron beam lithography, thermal evaporation and liftoff technique on electron transparent membrane substrates. The magnetic properties have been studied by Lorentz transmission electron microscopy. In situ magnetizing experiments have been carried out to obtain information about the nucleation and propagation of magnetic domains within the permalloy nanodisks and to determine the nucleation and saturation fields. The diameter of the patterned elements has been varied between 180 and 950 nm, the height was 15 nm. The experiments showed that the vortex configuration is the most favorable state in zero field conditions of all investigated permalloy nanodisks.

Magnetic vortices play an important role in the switching behavior of micron- and submicron-sized ferromagnetic elements. We have prepared submicron permalloy elements by a combination of electron-beam lithography and liftoff technique on electron transparent membrane substrates. The magnetization reversal mechanism and the remanent magnetization configuration were observed by means of Lorentz transmission electron microscopy. In remanence, the investigated structures form a vortex configuration. In situ magnetizing experiments showed the possibility of adjusting the sense of magnetization rotation by introducing a slight geometric asymmetry to the otherwise circular nanostructures.

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