Modification of Nanosphere Templates for Nanocap and Antidot Magnetic Thin Film Fabrication

Previous work with curved magnetic thin films, such as nanocap thin films, has suggested the formation of magnetic vortex states that arise from their geometry. Furthermore, controlling the size and shape of the particles used for templates during fabrication may help tune the magnetic behavior. This study aims to better understand the parameters that give rise to these magnetic states - such as nanosphere diameter, nanocap shape, and gap between the nanocaps - by modifying polystyrene nanosphere templates. Templates were modified via reactive ion etching (RIE), or by removing the nanosphere monolayer to create antidot thin films. Investigation into the etching of nanosphere templates by changing gas pressure and etching time, as well as comparing different particle sizes, achieved a recipe for a controlled etching. Focused ion beam (FIB) used for cross-sectional imaging show the etched nanospheres change to spheroid shapes and sheds light on the coverage during thin film deposition. Magnetic hysteresis loop measurements were carried out to observe switching property, and magnetic force microscopy to visualize the magnetic configuration of these modified nanocap thin films.