Magnetization dynamics of perpendicular writers

The magnetization dynamics of perpendicular writers was studied by using micromagnetic finite element models (micromagnetic-FEM). The obtained head response is different from a conventional dynamic-FEM result, and it shows the head field rise time of 0.5-0.6 ns, same as a longitudinal writer's one. During the switching process the head field has distortions under the write shield and an opposite polarity emphasis at the write shield edge in the profile. These phenomena are related to the flux sink region of the soft-magnetic underlayer (SUL), the interaction between SUL and the write shield, and the SUL domains switching; they can cause a wide-range erasure.