Full micromagnetics of recording on patterned media

Numerical micromagnetics of the bit writing process revealed the theoretical limits for remanence, coercive field, switching behaviour at a short time scale of less than 1 ns for patterned recording media. We discuss our recent results concerning the influence of the granular microstructure on the fast switching processes of typical CoCrPtX, FePt and CoPd thin films used for high density magnetic recording with longitudinal and perpendicular anisotropy. In detail, we will show that the degree of the exchange coupling between neighbouring grains, the grain size and its distribution and the offset between recording head and bit structure finally control the magnetization reversal properties of the individual bits.