Magnetic nanostructures with defined magnetic states fabricated by focused ion beam

A comparative analysis of the effects of Ga+-focused ion beam (FIB) on the magnetic properties of nanostructures was conducted in this study. It shows that the FIB cuts that cause the structures to switch from the initial vortex to the single-domain ("snake-like") states do not require complete physical separation of the elements. Numerical simulations indicate that a remaining 3–5 nm or less magnetic material in a 20–30 nm thick permalloy layer can cause the switching. These results were partially confirmed experimentally, where grooves with a depth between 15–30 nm caused the switching. The addition of a titanium buffer layer significantly improves the accuracy and quality of the FIB cuts by reducing the amount of redeposited material.