Simulations of recording in composite media

In this paper, the recording performance of two types of media are compared by calculating the head field distribution of an 80 nm wide write pole in conjunction with a soft magnetic underlayer. The maximum effective field was inclined 15deg from the perpendicular axis. The effective head field gradient was a maximum when the head field was inclined 35deg from the perpendicular. Composite media have some advantages over single layer media. However, the difference in Hc(thetas) at the angle where recording takes place is much less than the difference in Hc(0). As a result, a significant reduction in the grain size, while increasing the uniaxial anistropy, Ku to maintain thermal stability, will not be possible as the media will become unwriteable.