Abstract
For bit-patterned and heat-assisted magnetic recording media, the essential basis is the (001) textured L10 FePt exchange spring magnet. In this dissertation we firstly realize this spring magnet and then investigate the corresponding magnetization reversal modes. We show that in a single-layered FePt film the L10 ordering is accompanied by the film agglomeration, resulting in the ordered but ruptured film. By introducing an FeOx capping layer we can suppress the film agglomeration while preserve the L10 ordering, leading to the desired continuous and (001)-oriented L10 FePt layer. Using the atomistic spin model we then investigate the magnetization reversal modes in the L10 FePt patterned dot with the soft magnetic edge, which could be caused by patterning damage. We show that the nucleation dominates the magnetization reversal at all studied edge-widths. As the edge-width increases the individual nucleation event, which can be described by the droplet and the antidroplet, turns into the multiple nucleation events, and the required nucleation field decreases and saturates. Finally, we investigate the magnetization reversal behaviors in L10 FePt exchange spring magnets with soft magnetic layers of varied Curie temperature (Tc), which are crucial for the thermally induced error. We show that for the domain-wall assisted reversal the increased Tc of the soft layer increases the required soft-layer thickness, which further increases at elevated temperatures. For the heat-assisted magnetic recording the increased soft-layer thickness sacrifices the heat efficiency and is therefore undesirable. All the results indicate that in the bit-patterned and heat-assisted recording media, a thin soft magnetic layer preserves the heat efficiency, and the soft magnetic edges with controllable properties could achieve the domain-wall assisted reversal.