Regensburg 2013 – scientific programme

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MA: Fachverband Magnetismus

MA 11: ThyssenKrupp Electrical Steel Dissertationspreis 2013 der AG Magnetismus

MA 11.2: Talk

Monday, March 11, 2013, 12:40–13:05, H3

Tailoring the magnetic vortex nucleation conditions in soft magnetic disks by means of introducing a — •Norbert Martin — Helmholtz-Zentrum Dresden-Rossendorf, 01099 Dresden

N. Martin Magnetic vortex structures are a promising candidate for magnetic data storage hence two bits can be stored per vortex, that is the chirality of the in plane magnetization and the orientation of the vortex core. This allows a higher data storage density. There are, however, lower limits in the size of magnetic elements in which a vortex can nucleate. One issue is thereby the magnetic field which is necessary in order to nucleate a vortex.

In the presented work a method is developed in order to decrease the nucleation field in a defined way by means of introducing a geometric asymmetry in the out of plane direction. The so caused decrease in the nucleation field is shown by micromagnetic modeling and experiments.

The asymmetry is introduced experimentally by masking a Permalloy thin film with a closely packed monolayer of nanospheres and subsequently irradiating the masked film with ions. The formation of magnetic vortices in such structures is proved by magneto-optic investigations and magnetic force microscopy. According to this dense arrays of small disks with magnetic vortices can be formed, which opens a way to higher data storage density.