3-D write field and imaging from multilayered soft films in perpendicular recording media

Write fields for a perpendicular recording medium with multiple soft magnetic keeper layers beneath the recording layer in three dimensions are described as a function of permeability and permeability anisotropy using imaging. Compared to two-dimensional calculations, there is significant reduction in the write field magnitude for the 3-D case. Variation of the soft layer permeability from 10 to 100 and in-plane permeability anisotropy ratio from 1 to 0.01 show only minor effects on the perpendicular write field. A bigger effect during write will be the edge writing by the tangential field into the soft magnetic layer(s). This edge writing can result in significant track edge signal interference.