We compute the switching field in a disk-shaped polycrystalline exchange-coupled bit (similar material to those found in bit-patterned media (BPM)) with micromagnetics, by varying physical parameters of a test grain. It was found that the size and the anisotropy of the test grain have substantial effects on the switching field, while its location has only minor influence. Scaling of the bit and the test grain dimensions result in similar switching properties. Switching field was reduced when the number of the low anisotropy test grains increased. Additionally, it was established that the intergranular exchange coupling needs to be at least 10% of the intragrain exchange for the bit to behave as one exchange-coupled entity. This investigation provides some insights for optimizing the material microstructure for the BPM application.
ASJC Scopus subject areas
- Physics and Astronomy(all)