Magnetic nanostructures for non-volatile memories

• Two methods were used to fabricate submicron nanomagnets.
• Magnets prepared by lift-off had vertical sidewalls without fencing features.
• The nanomagnet mask pattern was optimized for ion-milling etch.
• Angular dependence of the ground state was calculated by micromagnetic simulation.
• The state of the nanomagnet is controlled by field direction.

In this work we present two fabrication approaches for patterning submicron Pacman-like (PL) magnetic nanoelements, the additive and subtractive process. Within the first process, PL structures are revealed using a standard lift-off technique. The second one is based on argon ion milling through titanium mask patterns. In the PL magnet the missing sector itself represents a dipole, which together with the external field, controls the chirality of the nucleated vortex. In order to determine the chirality of the vortex ground state, an array of PL nanomagnets of the diameter 200 nm prepared by the subtractive process, is mapped by the magnetic force microscopy. The experimental results are in good agreement with the results achieved by the micromagnetic simulations.

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